Tenses – NDA English Notes

1. Introduction

Tenses is the largest confirmed grammar chapter in the JOVIK NDA English series. Tenses are not simply labels for time. They encode both the time of an event (past, present, future) and its aspect: whether the action is simple, ongoing (continuous), completed (perfect), or ongoing-and-completed (perfect continuous). When a student uses the wrong tense, they produce a grammatically wrong sentence even when the meaning is broadly clear.

The chapter’s central principle:

★ IMPORTANT Every clause requires a tense that is determined not only by when the event happened, but by its aspect, its relationship to other events in the sentence, and the grammatical structure of the clause it appears in.

The chapter has five confirmed examination areas. Conditional sentence tense sequences account for fourteen of the thirty questions, more than any other grammar concept tested anywhere in NDA English. Present Perfect and its triggers account for eight. Future tense in time clauses, past tense selection, and tense consistency account for the remaining eight. This chapter rewards careful study more than any other in the series.

2. The English Tense System: A Conceptual Map

English has twelve tense-aspect combinations formed by three time frames (past, present, future) and four aspects (simple, continuous, perfect, perfect continuous). Before studying specific rules, it helps to see the full system in one view. Every confirmed NDA tense error is a failure to select the correct cell from this system.

Aspect	Past	Present	Future
Simple	did, went, arrived  “She went home.”	do, go, arrive  “She goes home.”	will do, will go  “She will go home.”
Continuous	was doing, was going  “She was going home.”	is doing, is going  “She is going home.”	will be doing  “She will be going.”
Perfect	had done, had gone  “She had gone home.”	has/have done  “She has gone home.”	will have done  “She will have gone.”
Perfect Continuous	had been doing  “She had been going for hours.”	has/have been doing  “She has been going for hours.”	will have been doing  “She will have been waiting.”

The NDA examiner almost never tests whether a student knows the name of a tense. The test is always whether the student can select the correct form for a specific grammatical context. The system above is the reference map; the sections that follow teach the specific selection rules that the examiner has confirmed.

3. Conditional Sentences: The Chapter’s Dominant Concept

Fourteen of the thirty confirmed NDA questions in this chapter test conditional sentence tense sequences. This makes conditional sentences the most tested grammar concept in all of NDA English. The examiner has returned to this concept every year between 2014 and 2024, across all four question formats. No student who has not mastered conditionals can reliably pass the NDA English tense section.

A conditional sentence has two parts: the if-clause (the condition) and the main clause (the result). The tense used in each part is determined by the type of conditional, whether the condition is real, hypothetical, or impossible.

★  IMPORTANT “WILL” NEVER FOLLOWS “IF” IN A CONDITIONAL SENTENCE. This is the most confirmed single error in NDA English.   “If you will come” is always wrong. “If you come” (first conditional)  ·  “If you came” (second conditional)  ·  “If you had come” (third conditional) — these are the only options.

The Complete Conditional Reference Table

Type	Condition	If-Clause Form	Main Clause Form	Time Reference	NDA Confirmed Error
Zero	General truth, always true	Present Simple	Present Simple	Timeless	“If you heat water to 100°C, it boils.”: not commonly tested
First	Real future possibility	Present Simple (NEVER “will”)	will / shall + base verb	Future: possible	“If you come with me, I shall be happy.”  [NDA 2014-I]  Error: “If you will come with me”
Second	Hypothetical: unlikely or imaginary present/future	Past Simple (“were” for all persons)	would / could + base verb	Present / Future: unreal	“If I were a millionaire, I would help the poor.”  [NDA 2016-II]  Error: “I would have helped”
Third	Impossible: refers to past that did not happen	Had + past participle (NEVER “have”)	Would have + past participle	Past: impossible	“If you had asked me, I would have told you.”  [NDA 2022-II]  Error: “If you have asked”
Mixed	Impossible past condition → hypothetical present result	Had + past participle	Would + base verb	Past condition; Present result	“If he had got his enemy, he would crush him.”  Error: mixing past simple + would have  [NDA 2014-II]

First Conditional: The Most Tested Error: “Will” in the If-Clause

The first conditional is used for real, possible future conditions. The if-clause uses the present simple; the main clause uses “will” or “shall”. The most confirmed individual error in the entire NDA English grammar corpus is inserting “will” into the if-clause of a first conditional.

“Will” belongs in the main clause of a first conditional: never in the if-clause.

Correct:  “If you come with me, I shall be happy.”

Incorrect:  “If you will come with me, I shall be happy.”

NDA 2014-I: Sentence Improvement:

“If you will come with me I shall be happy.”  Error: “will come” → Correct: “come” (present simple in if-clause)  [NDA 2014-I]

NDA 2017-I: Spotting Errors:

“I can fly/(a) if I will be/(b) a bird.”  Error: Part (b): “if I will be” → Correct: “if I were a bird”  [NDA 2017-I]

NDA 2019-I: Spotting Errors:

“If Ramesh will be promoted/(a) he will get/(b) a higher salary.”  Error: Part (a): “will be promoted” → Correct: “is promoted”  [NDA 2019-I]

NDA 2022-II: Spotting Errors:

“If I will be the millionaire/(a) I would eradicate/(b) poverty.”  Error: Part (a): “will be” → Correct: “were” (second conditional)  [NDA 2022-II]

NDA 2015-II: Sentence Improvement:

“I will be happy if you will buy me apples.”  Error: “will buy” → Correct: “buy” (present simple in if-clause)  [NDA 2015-II]

Five separate NDA papers have confirmed this exact error. A student who has internalised the rule (“will never follows if in a conditional sentence”) eliminates the most productive single source of tense errors in the examination.

Second Conditional: Hypothetical Present or Future

The second conditional describes a hypothetical situation that is unlikely, imaginary, or contrary to the current reality. The if-clause uses the past simple (or “were” for all persons, especially with “be”). The main clause uses “would + base verb”.

Pattern: If + past simple (use “were” for “be”: all persons), main clause: would + base verb

Correct:  “If I were a millionaire, I would help the poor.”

Incorrect  “If I were a millionaire, I would have helped the poor.”  This is third conditional.

NDA 2016-II: Sentence Improvement:

“If I were a millionaire, I would have helped the poor.”

Underlined: “I would have helped”  |  Options: (a) am capable of helping  (b) could have helped  (c) would help  (d) No improvement

Answer: (c) would help  [NDA 2016-II]

“If I were” signals second conditional (hypothetical present). Second conditional main clause: would + base verb. “Would have helped” = third conditional main clause: wrong tense type.

NDA 2018-II: Fill in the Blanks:

“If I were rich, _____ a lot.”

Options: (a) I’ll travel  (b) I can travel  (c) I would travel  (d) I travelled

Answer: (c) I would travel  [NDA 2018-II]

“If I were” = second conditional. Main clause = would + base verb.

(a) “I’ll travel” = future simple: wrong for hypothetical.  (b) “I can travel” = ability: wrong.  (d) “I travelled” = simple past: not main clause form.

NDA 2024-II: Sentence Completion:

“What would you do _________?”

Options: (a) if you found your lost toy  (b) if you will have found your lost toy  (c) if you would found your lost toy  (d) if you have find your lost toy

Answer: (a) if you found your lost toy  [NDA 2024-II]

Main clause: “would do” = second conditional. If-clause: past simple “found”: correct.

(b) “will have found”: future perfect in if-clause; will never follows if.  (c) “would found”: “would” in if-clause is non-standard.  (d) “have find”: wrong form entirely.

Third Conditional: Impossible Past

The third conditional refers to a condition in the past that did not happen, so the result is also impossible. The if-clause uses “had + past participle”; the main clause uses “would have + past participle”.

Pattern: If + had + past participle, main clause: would have + past participle

Correct:  “If you had asked me, I would have told you.”

Incorrect:  “If you have asked me, I would have told you.”  Present Perfect in if-clause is wrong.

NDA 2022-II: Spotting Errors:

“If you have asked me/(a) for the truth I would have told/(b) you at that time.”

Error: Part (a): “have asked”  |  Correct: “If you had asked me…”  [NDA 2022-II]

Third conditional requires “had + past participle” in the if-clause. “Have asked” = present perfect: wrong aspect for past impossible condition.

NDA 2015-I: Spotting Errors:

“If I had known/(a) this earlier/(b) I will have helped him./(c) No error.”

Error: Part (c): “I will have helped him”  |  Correct: “I would have helped him.”  [NDA 2015-I]

Third conditional if-clause: “had known” ✓. Third conditional main clause: “would have helped”: NOT “will have helped”. “Will” never appears in conditional main clauses of the third type.

NDA 2015-I: Sentence Improvement:

“I would have waited for you at the station if I knew that you would come.”

Underlined: “I knew”  |  Options: (a) had known  (b) was knowing  (c) have known  (d) No improvement

Answer: (a) had known  [NDA 2015-I]

Main clause: “would have waited” = third conditional. If-clause must match: “had known” (past perfect): not simple past “knew”.

Mixed Conditional: Wrong Combination of If-Clause and Main Clause

A mixed conditional refers to a past condition with a present result. It is a genuine grammatical structure, but students often produce accidental mixed sentences by incorrectly combining clauses from different conditional types. The examiner tests this error specifically.

NDA 2014-II: Sentence Improvement:

“If he got his enemy in his hand, he would have crushed him to death.”

Underlined: “got”  |  Options: (a) has got  (b) was getting  (c) had got  (d) No improvement

Answer: (c) had got  [NDA 2014-II]

Main clause: “would have crushed” = third conditional main clause. If-clause must match: “had got” (past perfect): not simple past “got”.

“Got” (second conditional if-clause) + “would have crushed” (third conditional main) = accidental mix.

Correct third conditional: “had got…would have crushed.”  OR  Correct second conditional: “got…would crush.”

“If You Were to”: Hypothetical Future

“If you were to + base verb” signals a formal or tentative hypothetical about a future possibility. The main clause requires “would + base verb”, not “will”.

NDA 2023-II: Spotting Errors:

“If you were to/(a) come to Chennai to settle down/(b) it will be the best possible decision./(c)”

Error: Part (c): “it will be”  |  Correct: “it would be the best possible decision.”  [NDA 2023-II]

“If you were to come” = hypothetical future (formal register). Hypothetical → main clause: “would be”: not “will be”. “Will” signals factual future; “would” signals hypothetical.

4. Hypothetical Constructions: Wish, As If, and Related Forms

Several English constructions beside “if” express hypothetical or subjunctive meaning. They share a common principle: the verb in the clause that follows them takes a tense that is “shifted back” from what the actual time of the event would suggest. This shift signals that the construction is hypothetical, not factual.

Construction	Tense Required	Meaning	Example	NDA Paper
wish (present)	Past Simple	Desire for something currently untrue	“I wish I knew her.” (I don’t know her now)	NDA 2021-I FITB
wish (past)	Past Perfect	Regret about something that happened / didn’t happen	“I wish I had known her before we met.”	NDA 2021-I FITB
wish (ability)	“could” + base	Desire for an ability one doesn’t have	“I wish I could help you.” (I cannot)	NDA 2024-II SC
as if / as though	“were” (all persons)	Hypothetical comparison: manner of appearance	“He looks as if he were weary.”	NDA 2017-II FITB
if I were you	Past “were” + “would”	Advice framed as a hypothetical	“If I were you, I wouldn’t buy that dress.”	NDA 2024-II SC
if you were to	Past “were to” + “would”	Formal hypothetical future	“If you were to come, it would be best.”	NDA 2023-II SE
it’s time	Past Simple	Polite urgency: thing should happen now	“It’s time you went home.”	Standard syllabus

“As If” Requires the Subjunctive “Were”

“As if” introduces a clause that compares someone’s appearance or behaviour to a hypothetical situation. Standard formal English uses the subjunctive “were”, not “is”, “was”, or “would be”, in this clause for all persons (he, she, it, I, you, they).

NDA 2017-II: Fill in the Blanks:

“He looks as if he _________ weary.”

Options: (a) is  (b) was  (c) would be  (d) were

Answer: (d) were  [NDA 2017-II]

“As if” in formal English requires the subjunctive “were” for all persons.

(a) “is”: indicative present: treats the appearance as a factual statement.

(b) “was”: informal; acceptable in spoken English but tested as wrong here.

(c) “would be”: conditional: wrong grammatical form after “as if”.

(d) “were”: subjunctive: correct in formal standard English.

“Wish”: Three Different Tense Requirements

“Wish” is followed by different tenses depending on whether the wish is about the present, the past, or an ability.

NDA 2021-I: Fill in the Blanks:

“I wish I _________ her before we met.”

Options: (a) know  (b) have known  (c) knew  (d) known

“Before we met” indicates a past event. Correct: “I wish I had known her before we met.”: past wish = past perfect.  [NDA 2021-I]

(a) “know” = present indicative: never after “wish”.  (b) “have known” = present perfect: wrong for past wish.  (c) “knew” = present wish (I wish I knew her now): wrong for past.  (d) “known” = incomplete form.

Rule summary:  I wish I KNEW her. → present wish (I don’t know her now): past simple

I wish I HAD KNOWN her. → past wish (I didn’t know her then): past perfect

NDA 2024-II: Sentence Completion:

“I wish _________.”

Options: (a) I could help you  (b) I ought to help you  (c) I did help you  (d) I must help you

Answer: (a) I could help you  [NDA 2024-II]

Wish about present ability: “wish + could + base verb”. “I wish I could help you” = I am unable to help you (present) and I wish I could.

NDA 2024-II: Sentence Completion:

“If I were you _________.”

Options: (a) I shouldn’t buy that dress  (b) I wouldn’t buy that dress  (c) I weren’t buying that dress  (d) I mustn’t buying that dress

Answer: (b) I wouldn’t buy that dress  [NDA 2024-II]

“If I were you” = second conditional / hypothetical advice. Main clause: “would + base verb”: “wouldn’t buy”.

(a) “shouldn’t”: obligation/advice; not standard second conditional here.  (c) “weren’t buying”: non-standard.  (d) “mustn’t buying”: wrong modal + wrong verb form.

5. Present Perfect and Present Perfect Continuous

Eight confirmed NDA questions test this area, the second largest concept group in the chapter. Every error involves either using the wrong tense where Present Perfect (or Present Perfect Continuous) is required, or using Present Perfect where simple past is required. The determining factor in every case is the time adverbial in the sentence.

The semantic key to the Present Perfect is this: it builds a bridge from a past event to the present moment. Simple past describes an island in the past, an event with a specific past time. Present Perfect describes a period or experience that connects to now.

“Since” vs “For”: The Most Confirmed Present Perfect Trigger

“Since” = starting point of a period. It tells you WHEN the period began.

“For” = duration of the period. It tells you HOW LONG the period has lasted.

Correct:  “I have been learning English for ten years.”  duration = ten years

Correct:  “I have been learning English since 2015.”  starting point = 2015

Incorrect:  “She has been teaching since five days.”  “since” needs a starting point, not a duration.

Trigger	Rule	Required Tense	Example	NDA Paper
“since” + starting point	Action continues from that point to now	Present Perfect or PPC	“have been living since they were married”	NDA 2011-I
“for” + duration	Action continues over that period to now	Present Perfect or PPC	“have been advising him for a long time”	NDA 2016-II
“for the last N days”	Duration continuing to present moment	Present Perfect Continuous	“have been on strike for the last fifteen days”	NDA 2016-II
“since” with a duration (error)	“since” cannot precede a duration	Use “for” instead	“since five days” → “for five days”	NDA 2013-I
“just”, “already”, “yet”	Recent action with present relevance	Present Perfect	“I have just finished.”	Standard syllabus
“ever”, “never”	Experiential: at any point in life	Present Perfect	“Have you ever been to Paris?”	Standard syllabus

NDA 2009-I: Spotting Errors:

“I am learning English/(a) for ten years/(b) without much effect./(c) No error.”

Error: Part (a): “I am learning”  |  Correct: “I have been learning English for ten years.”  [NDA 2009-I]

“For ten years” with an action from past to present → Present Perfect Continuous. “Am learning” = simple present continuous: cannot express the “from past to now” meaning.

NDA 2015-II: Fill in the Blanks:

“I want to study Geology now for I _____ Zoology for the last three years.”

Options: (a) am studying  (b) have been studying  (c) had studied  (d) had been studying

Answer: (b) have been studying  [NDA 2015-II]

“For the last three years” = duration from past to present now. Present Perfect Continuous: ongoing action from past to now.

(a) no past-to-now connection.  (c) ends in the past.  (d) same issue as (c).

Present Perfect with Specific Past-Time Adverbials: Use Simple Past Instead

When a time adverbial names a definite, specific point in the past (“yesterday”, “last week”, “three years ago”, “on Monday”, “in 2010”), the event is anchored to that specific past moment. This removes the “bridge to the present” that defines Present Perfect. Simple past is required.

Specific past-time adverbials (yesterday, last week, N years ago, on Monday, in [year]) → Simple Past

Correct:  “I met him on Monday last.”  [NDA 2011-II correction]

Incorrect:  “I have met him on Monday last.”  Past time adverbial cannot co-occur with Present Perfect.

NDA 2012-II: Spotting Errors:

“I have seen him/(a) going to the theatre/(b) with his friends yesterday evening.”

Error: Part (a): “have seen”  |  Correct: “I saw him…yesterday evening.”  [NDA 2012-II]

NDA 2012-II: Spotting Errors:

“He has taken charge/(a) as principal of our college/(b) three years ago.”

Error: Part (a): “has taken charge”  |  Correct: “He took charge…three years ago.”  [NDA 2012-II]

NDA 2011-II: Spotting Errors:

“I have met him/(a) on Monday last/(b) and had a long discussion.”

Error: Part (a): “have met”  |  Correct: “I met him on Monday last.”  [NDA 2011-II]

Present Perfect Continuous: Ongoing Action to the Present Moment

NDA 2024-II: Sentence Completion:

“I hope the bus comes soon because _________.”

Options: (a) we waited for half an hour  (b) we have been waiting for half an hour  (c) we waiting for half an hour  (d) we could have been waiting for half an hour

Answer: (b) we have been waiting for half an hour  [NDA 2024-II]

The waiting started in the past and is still continuing now. Present Perfect Continuous = ongoing action from past to now.

(a) “waited” = simple past: implies waiting ended.  (c) “we waiting”: ungrammatical.  (d) “could have been waiting”: conditional perfect; wrong for factual ongoing state.

NDA 2017-II: Fill in the Blanks:

“Years _________ since I saw her last.”

Options: (a) have passed  (b) had passed  (c) had been passing  (d) have been passing

Answer: (a) have passed  [NDA 2017-II]

“Years have passed since I saw her last”: the passing of years is an elapsed period from a past event to the present. Present Perfect = correct. (b) “had passed” = past perfect: would require another past event as the reference point.

6. Future Tense in Time Clauses

Five confirmed NDA questions test the rule that time clauses use the present tense (not “will” or “shall”) even when referring to future events. This rule applies to clauses introduced by specific time conjunctions.

★  IMPORTANT After these time conjunctions, use the PRESENT TENSE for future meaning: never “will” or “shall”:   when  ·  as soon as  ·  before  ·  after  ·  till  ·  until  ·  once  ·  by the time   Mnemonic: WABATU (When · As soon as · Before · After · Till · Until)

Time Conjunction	Tense Required in Clause (Future Meaning)	Example	NDA Paper
when	Present Simple	“I will call you when I arrive.” (not “will arrive”)	Standard
as soon as	Present Simple	“I shall leave as soon as I find a job.” (not “shall find”)	NDA 2015-II
before	Present Simple or Present Perfect	“Before you leave, say goodbye.”	Standard
after	Present Perfect (formal) / Present Simple	“After I have saved money, I shall go.”	NDA 2015-II SI
till / until	Present Simple	“Do not fire till I give the order.” (not “will give”)	NDA 2014-I
by the time	Present Perfect	“By the time you arrive, I will have finished.”	NDA 2011-I
once	Present Simple	“Once you finish, you may leave.”	Standard syllabus

NDA 2015-II: Spotting Errors:

“I shall leave school/(a) as soon as/(b) I shall find a job./(c) No error.”

Error: Part (c): “I shall find”  |  Correct: “as soon as I find a job.”  [NDA 2015-II]

“As soon as” is a time conjunction. Future meaning in this clause uses present simple. “I shall find” incorrectly inserts the future auxiliary into the time clause.

NDA 2014-I: Spotting Errors:

“The general said, ‘Soldiers, do not fire/(b) till I will give the order.’/(c)”

Error: Part (c): “till I will give”  |  Correct: “till I give the order.”  [NDA 2014-I]

“Till” is a time conjunction. Present simple for future meaning in time clause.

NDA 2011-I: Spotting Errors:

“By the time you arrive tomorrow/(a) I have finished/(b) my work./(c) No error.”

Error: Part (b): “I have finished”  |  Correct: “I will have finished my work.”  [NDA 2011-I]

“By the time + present simple” is the time clause (correct: “you arrive”). The main clause (outside the time clause) requires the future perfect: “will have finished.” “Have finished” = present perfect: cannot express the future-perfect meaning here.

NDA 2016-I: Sentence Improvement:

“In a few minutes’ time, when the clock strikes six, I would be waiting here for an hour.”

Underlined: “would be waiting”  |  Options: (a) shall be waiting on  (b) shall have been waiting  (c) shall wait  (d) No improvement

Answer: (b) shall have been waiting  [NDA 2016-I]

“When the clock strikes six” = time clause (present simple correctly used). At that future point, the waiting will have been in progress for a completed duration. Future Perfect Continuous: “shall have been waiting”: correct. “Would be waiting” = conditional continuous: wrong for a factual future statement.

7. Past Tense Selection in Narrative Context

Six confirmed NDA questions test the selection of the correct past tense when describing events that have a time relationship to each other. The key is understanding the hierarchy of past tenses in English narrative.

Narrative Tense Hierarchy:

1. Simple Past: main narrated events (“She arrived at six.”)

2. Past Continuous: background or interrupted actions (“She was reading when he arrived.”)

3. Past Perfect: actions completed before another past event (“She had finished by the time he arrived.”)

Past Continuous for Background and Interrupted Actions

When one action was in progress and another action interrupted or occurred during it, the in-progress action uses the past continuous. The interrupting action uses the simple past.

NDA 2017-I: Sentence Improvement:

“When we saw him last, he ran to catch a bus.”

Underlined: “ran”  |  Options: (a) has run  (b) had run  (c) was running  (d) No improvement

Answer: (c) was running  [NDA 2017-I]

“When we saw him” = simple past (the observing event). The running was in progress when we saw him. Background action in progress → past continuous: “he was running to catch a bus.”

NDA 2014-II: Sentence Improvement:

“My friend met me, unexpectedly, when I looked for a taxi, desperately.”

Underlined: “looked”  |  Options: (a) had looked  (b) was looking  (c) had been looking  (d) No improvement

Answer: (b) was looking  [NDA 2014-II]

The meeting was unexpected: it happened while the looking was in progress. Background/interrupted action → past continuous: “when I was looking for a taxi.”

NDA 2015-I: Sentence Improvement:

“Five years ago on this date, I am sitting in a small Japanese car, driving across Poland.”

Underlined: “am sitting”  |  Options: (a) was sitting  (b) sat  (c) have been sitting  (d) No improvement

Answer: (a) was sitting  [NDA 2015-I]

“Five years ago on this date” = a past time reference. “Am sitting” = present continuous: wrong for a past narrative. The state of sitting was in progress at that past point → past continuous.

Past Perfect for the Earlier of Two Past Events

When two events both happened in the past, the event that happened earlier uses the past perfect. The event that happened later uses the simple past.

NDA 2010-I: Spotting Errors:

“Pooja went to her friend’s house at the appointed hour; but/(a) she was told/(b) that her friend left half an hour earlier./(c) No error.”

Error: Part (c): “left half an hour earlier”  |  Correct: “that her friend had left half an hour earlier.”  [NDA 2010-I]

Two past events: (1) friend left: earlier; (2) Pooja told: later. Earlier event: past perfect → “had left.” “Left” (simple past) fails to signal that this happened before Pooja’s arrival.

NDA 2017-I: Fill in the Blanks:

“When I met John yesterday, it was the first time I _________ him since Christmas.”

Options: (a) saw  (b) have seen  (c) had seen  (d) have been seeing

Answer: (c) had seen  [NDA 2017-I]

“It was the first time” + a past reference → past perfect in the embedded clause. “Had seen” = past perfect: describes the seeing (last at Christmas) as earlier than the meeting (yesterday).

(a) “saw” = simple past: would imply both seeing and meeting were simultaneous.  (b) “have seen” = present perfect: wrong aspect for a past narrative.

NDA 2014-II: Sentence Improvement:

“Everybody who finished writing can go home.”

Underlined: “finished”  |  Options: (a) had finished  (b) have finished  (c) has finished  (d) No improvement

Answer: (c) has finished  [NDA 2014-II]

“Can go home” = present: permission given now. The condition (finishing writing) must be completed relative to now → Present Perfect. “Has finished” = correct: those who have finished (by now) can go home.

(a) “had finished” = past perfect: would imply an earlier past reference point.  (b) “have finished” = wrong agreement (everybody is singular).

8. Reported Speech and Tense Backshift

When a reporting verb is in the past tense (“said”, “told”, “advised”, “asked”), the tense of the reported clause typically shifts one step back: present → past; past → past perfect. This is called tense backshift.

Direct Speech Tense	Reported Speech Tense (after past reporting verb)
Present Simple: “I go to school”	Past Simple: He said he went to school
Present Continuous: “I am going”	Past Continuous: He said he was going
Present Perfect: “I have finished”	Past Perfect: He said he had finished
Past Simple: “I went”	Past Perfect: He said he had gone
Will: “I will help”	Would: He said he would help

NDA 2011-II: Spotting Errors:

“The doctor advised me/(a) that/(b) I am going on a salt free diet./(c) No error.”

Error: Part (c): “I am going”  |  Correct: “the doctor advised me that I was going on a salt-free diet.”  [NDA 2011-II]

Reporting verb “advised” is past tense. Tense backshift: present continuous “am going” → past continuous “was going”.

The “Yesterday” Exception: Context-Sensitive Backshift

Backshift is not automatic in all contexts. When a specific past time adverbial (“yesterday”, “last week”, “on Monday”) is present in the reported clause, the past tense of the event (not past perfect) is usually appropriate, because “yesterday” already anchors the event to a specific past point relative to the moment of speaking.

NDA 2026-I: Spotting Errors:

“When I saw Arnab/(a) he said he/(b) had taken his/(c) driving test yesterday./(d)”

Error: Part (c): “had taken”  |  Correct: “he said he took his driving test yesterday.”  [NDA 2026-I]

“Yesterday” anchors the driving test to the same day as the seeing/saying. “Had taken” = past perfect: implies the test happened even further back. With “yesterday” as anchor: simple past “took” is contextually correct.

This is the most analytically sophisticated tense question in the confirmed corpus.

9. Tense Consistency

Within a sentence or narrative, tenses must be internally consistent. Mixing present and past tense in the same narrative (without a structural reason) is an error. Two confirmed NDA questions test this.

NDA 2010-I: Spotting Errors:

“Whenever a person lost anything/(a) the poor folk around/(b) are suspected./(c) No error.”

Error: Part (c): “are suspected”  |  Correct: “the poor folk around were suspected.”  [NDA 2010-I]

“Lost” (simple past) establishes a past narrative frame. “Are suspected” (present) breaks the tense consistency. Both clauses must use the same past tense.

NDA 2019-II: Spotting Errors:

“Most of us who are older competitive runners/(a) are not able to race anywhere at the same speed/(b) as we do when we were 30./(c) No error.”

Error: Part (c): “as we do when we were 30”  |  Correct: “as we did when we were 30.”  [NDA 2019-II]

“When we were 30” establishes a past time frame. “We do” (present) is inconsistent. Correct: “as we did when we were 30”: both past.

10. Supplementary Tense Concepts

“Is Living” vs “Has Been Living”: Present State for Ten Years

NDA 2014-I: Sentence Improvement:

“He is living in this house for the past ten years.”

Underlined: “is living”  |  Options: (a) was living  (b) had been living  (c) has been living  (d) No improvement

Answer: (c) has been living  [NDA 2014-I]

“For the past ten years” = duration from past to present. Ongoing action from past to present → Present Perfect Continuous. “Is living” (simple present continuous) cannot express the “from past to now” meaning.

“It Is Raining” vs “Has Been Raining”: Action All Through This Week

NDA 2016-I: Sentence Improvement:

“It is raining heavily all through this week.”

Underlined: “is raining”  |  Options: (a) has rained  (b) rains  (c) rained  (d) No improvement

Answer: (a) has rained  [NDA 2016-I]

“All through this week” = from the beginning of the week to now. Action continuing from a past point to the present → Present Perfect. “Is raining” = simple present continuous: no past starting point expressed.

“Arrived” vs “Was Arriving”: Punctual Verb Cannot Use Continuous

NDA 2009-I: Spotting Errors:

“When he was arriving/(a) the party was/(b) in full swing. /(c) No error.”

Error: Part (a): “was arriving”  |  Correct: “When he arrived…”  [NDA 2009-I]

“Arrive” is a punctual verb: it happens at a moment, not over a period. Punctual verbs are not used in continuous forms for the event itself. “Was arriving” = continuous: wrong for a punctual event. “Arrived” = simple past: correct for the momentary event of arrival.

“It’s Time”: Requires Past Simple

“It’s time” + a clause expressing what should happen uses the past simple to signal polite urgency: the action should have started already.

Correct: “It’s time you went home.”  (not “go”)

Correct: “It’s time we left.”  (not “leave”)

Correct:  “It’s high time he stopped complaining.”  (not “stops”)

“After I Saved” vs “After I Have Saved”: Time Clause with Future Meaning

NDA 2015-II: Sentence Improvement:

“After I saved some money, I shall go abroad.”

Underlined: “saved”  |  Options: (a) shall save  (b) should have saved  (c) have saved  (d) No improvement

Answer: (c) have saved  [NDA 2015-II]

“After I [have saved]”: the saving must be completed before going abroad. Future time clause: Present Perfect (“have saved”) marks completion before main action.

(a) “shall save” = wrong: will/shall cannot appear in time clauses.  (b) “should have saved” = conditional: wrong for time clause.

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