📌 The One Idea Behind All Tense Questions: NDA never asks you to recite tense names. It places a sentence with a time signal — a word, phrase, or clause that tells you when the action happens — and checks whether the verb matches that signal. Learn the signals, and the tense chooses itself. This chapter is built entirely around that logic.
The Time Map — All Tenses at a Glance
Every tense occupies a position on the time line. The signal word in a sentence points to a position, and the verb must match it.
PART A — PRESENT TENSES
1 Simple Present & Present Continuous — Signal Words Decide
nowat this momentcurrentlyat presentlook!listen!right nowthis week/monthtoday (ongoing)
He is currently training. ✓
Look! The platoon is marching. ✓
She works right now. ✗ → is working
⚠
Stative Verbs — Never Used in Continuous Form
Verbs of mental state and perception do not take -ing even when “now/currently” is present: know, believe, understand, like, love, hate, want, need, own, belong, see, hear, smell, taste, mean, contain, consist.
✗ I am knowing the answer now. ✓ I know the answer.
NDA PYQSimple Present vs Present Continuous
Q1. (NDA 2024-I) Find the error: “(A) He is usually / (B) reporting to the base / (C) before dawn / (D) No error”
Answer: (A)/(B) “Usually” is a frequency adverb — it signals a habit → Simple Present. “Is reporting” (continuous) is wrong here. Correct: “He usually reports to the base before dawn.”
Q2. (NDA 2023-II) Find the error: “(A) The General / (B) is knowing / (C) the full details of the operation / (D) No error”
Answer: (B) “Know” is a stative verb — it cannot be used in continuous form. Correct: “The General knows the full details.”
PART B — PAST TENSES
2 Simple Past & Past Continuous — Signal Words Decide
Simple Past — V2 (past form)
Subject + V2 + …
Signal words → Simple Past (time clearly mentioned)
yesterdaylast week/month/yearagoin 1947 / in 2020that day / that morningthenin those daysoncewhen I was young
He joined the army three years ago. ✓
She passed the exam last year. ✓
India became independent in 1947. ✓
He has joined last year. ✗ → joined
Past Continuous — was/were + V-ing
Subject + was/were + V-ing + …
Signal: action ongoing in past (smaller time = during a span)
whilewhen (background action)all day / all nightthe whole morningat that timethroughout
It was raining when we arrived. ✓
While he was sleeping, the alarm went off. ✓
They marched all day. ✗ → were marching
💡 Key rule for Past Continuous: When two past actions happen simultaneously and one is the background/ongoing action (longer, interrupted), it takes Past Continuous; the shorter, sudden action takes Simple Past.
✓ He was reading when the phone rang. — reading = ongoing background; rang = sudden interruption.
3 Present Perfect — Unspecified Past with Present Relevance
Present Perfect — has/have + V3
Subject + has/have + V3 + …
Signal: past action whose exact time is unknown OR whose result is felt now
justalreadyyeteverneverrecentlylatelyso fartill now / up to nowsince [point]for [duration]
He has just returned from the mission. ✓
Have you ever served in a field unit? ✓
She has not submitted the form yet. ✓
He served here since 2018. ✗ → has served since 2018
⚠ THE most common NDA tense error — “since/for” with Simple Past:
“Since” marks a point in time from which an action started and is still ongoing → must use Present Perfect (or Perfect Continuous).
“For” marks a duration of an ongoing action → must use Present Perfect (or Perfect Continuous).
✗ He served in the army since 2015.
✓ He has served in the army since 2015.
✗ She waited for three hours. (if she is still waiting)
✓ She has waited for three hours.
4 Past Perfect — Past of the Past
Past Perfect — had + V3
Subject + had + V3 + …
Signal: two past actions — the earlier one takes Past Perfect
beforeafterby the timewhen (both past)hardly…whenno sooner…thanas soon asby [past time]
By the time reinforcements arrived, the soldiers had already secured the area. ✓
He had completed training before he was commissioned. ✓
Hardly had he arrived when it started raining. ✓
He completed training before he was commissioned. ✗ (earlier action needs had completed)
Example: By the time he arrived [Event 2], the briefing had already ended [Event 1].
NDA PYQPast Tenses — Simple Past vs Present Perfect vs Past Perfect
Q3. (NDA 2025-I) Find the error: “(A) He said / (B) that he has completed / (C) the mission the previous night / (D) No error”
Answer: (B) “The previous night” specifies a named past time. After a past reporting verb (“said”), use Past Perfect for the earlier action. Correct: “that he had completed the mission the previous night.”
Q4. (NDA 2024-II) Find the error: “(A) She has visited / (B) her home town / (C) last summer / (D) No error”
Answer: (A) “Last summer” is a specified past time. Present Perfect cannot be used with a named past time. Correct: “She visited her home town last summer.” (Simple Past). This is the single most repeated tense error in NDA papers.
Q5. (NDA 2023-I) Fill in the blank: “By the time the relief column arrived, the forward post ___ already fallen.”
(a) has
(b) had
(c) was
(d) have
Answer: (b) had “By the time + Simple Past” → the earlier event needs Past Perfect: had + V3. “Had already fallen” = the post fell before the column arrived. The signal “by the time” + past verb in the clause always triggers Past Perfect in the main clause.
PART C — PERFECT CONTINUOUS: THE SINCE / FOR FRAMEWORK
5 The Since / For Framework — Three Tenses from One Rule
Core Idea: “Since” and “for” describe an action that started in the past and is still continuing. The tense — Present, Past, or Future Perfect Continuous — is decided purely by where the end-point of the action lies on the time line.
No end time given → Present Perfect Continuous
Action started in past, still ongoing at the moment of speaking.
He has been serving since 2015. ✓
She has been waiting for two hours. ✓
They have been training since morning. ✓
Past end time given → Past Perfect Continuous
Action started earlier in past, continued up to a past reference point.
He had been serving for ten years when he was promoted. ✓
She had been waiting since dawn when help arrived. ✓
Future end time given → Future Perfect Continuous
Action started in past/present, will still be ongoing at a future time.
By next year, he will have been serving for a decade. ✓
By 2030, she will have been teaching for 20 years. ✓
💡 Since vs For — what each takes: Since = a point in time (starting moment): since 2015 / since morning / since childhood / since the war ended For = a duration (length of time): for ten years / for two hours / for a long time / for months
✗ since ten years | for 2015 — these are wrong because “ten years” is a duration (needs “for”) and “2015” is a point (needs “since”).
Decision flow — which tense with since/for? FILL IN THE BLANK
Action with since/for
→
Where does it end?
→
No end stated (still happening now)
→
has/have been + V-ing
→
End point is in the PAST
→
had been + V-ing
→
End point is in the FUTURE
→
will have been + V-ing
NDA PYQSince / For — Perfect Continuous Framework
Q6. (NDA 2025-II) Find the error: “(A) He is serving / (B) in the forward area / (C) since the last monsoon / (D) No error”
Answer: (A) “Since the last monsoon” = action started at a past point and is still ongoing. Use Present Perfect Continuous (no stated end = still happening now). Correct: “He has been serving in the forward area since the last monsoon.”
Q7. (NDA 2024-I) Fill in the blank: “She ___ for the exam since early morning and had not taken a break.”
(a) has been preparing
(b) had been preparing
(c) was preparing
(d) is preparing
Answer: (b) had been preparing The second clause “had not taken” tells us the reference point is in the past. The action started earlier and continued up to that past moment → Past Perfect Continuous: had been preparing. The end point is past (“had not taken” = past), so we use “had been”, not “has been”.
Q8. (NDA 2023-II) Find the error: “(A) They have been waiting / (B) since three hours / (C) for the results / (D) No error”
Answer: (B) “Three hours” is a duration — use “for”, not “since”. “Since” is used only with a specific point in time (since 3 o’clock / since morning). Correct: “for three hours”. The tense (have been waiting) is correct.
PART D — FUTURE TENSES
6 Future Tenses — Signal Words & the One-Will Rule
Simple Future — will + V1
Subject + will + V1 + …
Signal words → Simple Future
tomorrownext week/month/yearsoonin the futureshortlyin a weeklater
He will report tomorrow. ✓
She will join next month. ✓
Future Perfect — will have + V3
Subject + will have + V3 + …
Signal: action completed before a stated future time
by tomorrowby next weekby the time (future)by [future date]
By tomorrow, he will have finished the report. ✓
By next year, she will have served for a decade. ✓
7 The One-Will Rule — Future with Two Clauses
This is one of the most reliably tested rules in NDA Fill in the Blanks and Spotting Errors. When a sentence has two clauses — one talking about the future and one expressing a condition, time, or related action — only one clause gets “will”. The other clause uses Simple Present.
Rule — “will” in main clause only; time/condition clause → Simple Present
✓ If he trains hard, he will succeed. (condition: present; result: will)
✗ If he will train hard, he will succeed. (two “will” = wrong)
✓ When she arrives, I will inform you. (time clause: present; main: will)
✗ When she will arrive, I will inform you.
✓ As soon as he reaches the base, he will report in. ✓
✓ Before you leave, you will receive your orders. ✓
✓ Unless he applies before Friday, he will not be considered. ✓
Time/Condition conjunctions after which “will” is replaced by Simple Present:
whenifunlessas soon asuntil / tillbeforeafterby the timeonceprovided thatin case
NDA PYQFuture Tenses — One-Will Rule
Q9. (NDA 2025-I) Find the error: “(A) When he will return / (B) from the exercise, / (C) we will hold a debrief / (D) No error”
Answer: (A) “When” introduces a time clause. In future time clauses, “will” is replaced by Simple Present. Correct: “When he returns from the exercise”. The main clause “we will hold a debrief” correctly uses “will”.
Q10. (NDA 2024-II) Fill in the blank: “Unless you ___ the application before the deadline, it will not be considered.”
(a) will submit
(b) submit
(c) would submit
(d) are submitting
Answer: (b) submit “Unless” introduces a condition clause — use Simple Present, not “will”. The main clause already has “will not be considered”. Only one “will” per sentence in future constructions. Answer: “Unless you submit”.
Q11. (NDA 2023-I) Sentence Improvement: “By the time he will reach the camp, the briefing will be over.”
(a) By the time he reaches the camp
(b) By the time he will have reached the camp
(c) By the time he reached the camp
(d) No improvement needed
Answer: (a) By the time he reaches the camp “By the time” introduces a future time clause → Simple Present (“reaches”), not “will reach”. Option (b) “will have reached” is an unnecessarily complex form when “reaches” is sufficient. Option (c) uses past tense, which is wrong in a future context.
PART E — SIMULTANEOUS & CONSECUTIVE ACTIONS
8 Simultaneous Actions — While / When: Simple vs Continuous
Rule: When two actions happen at the same time in the past, the tense of each verb depends on its duration. The longer, ongoing action uses the Past Continuous. The shorter, sudden action uses the Simple Past. “While” introduces the ongoing action; “when” can introduce either.
Ongoing action (longer) → Past Continuous
While he was studying, the power went off.
While the soldiers were marching, it began to rain.
The officer was briefing the team when orders changed.
She was preparing her report when he called.
Sudden / complete action (shorter) → Simple Past
While he was studying, the power went off.
It began to rain while the soldiers were marching.
When orders changed, the officer was briefing the team.
Both simple past: When he entered, she stood up. (equally brief)
⚠ Two continuous actions simultaneously — both can take Past Continuous:
✓ While she was cooking, he was reading. (two ongoing, equally long actions — both continuous)
✗ While she cooked, he was reading. (asymmetric — one simple, one continuous — implies different durations)
NDA PYQSimultaneous Actions — While / When
Q12. (NDA 2024-I) Find the error: “(A) While the General / (B) was inspecting the troops, / (C) his aide delivered the message / (D) No error”
Answer: (D) No error This is a correct sentence: ongoing inspection (Past Continuous) is interrupted by the sudden delivery of the message (Simple Past). The structure “while + was V-ing … V2” is correct. NDA includes correct sentences to test whether students over-correct.
Q13. (NDA 2023-II) Find the error: “(A) When the patrol / (B) was entering the village, / (C) the villagers welcomed them / (D) No error”
Answer: (B) “Enter” is a short, momentary action — not a long ongoing one. It should not be in the Past Continuous. Correct: “When the patrol entered the village” (Simple Past). Contrast: “While the patrol was patrolling…” would be correct because patrolling is an extended action.
9 Consecutive Actions — had + V3 for the Earlier of Two Past Events
Rule: When two actions happen one after the other in the past, the earlier action uses Past Perfect (had + V3) and the later action uses Simple Past (V2). This establishes a clear sequence — the reader knows which happened first.
Consecutive past actions — had + V3 for the earlier, V2 for the later
✓ By the time he arrived [later], the meeting had already ended [earlier]. ✓
✓ He had finished [earlier] his training before he was commissioned [later]. ✓
✓ After she had submitted the form, she left the office. ✓
✓ No sooner had he sat down than the alarm sounded. ✓
✗ He finished his training before he was commissioned. (earlier action should be Past Perfect)
💡 “After / Before” — does tense still matter?
Technically, “after” and “before” already tell us the sequence. So in everyday English, Simple Past can be used for both. But in NDA Spotting Errors, if the sentence uses both “before/after” AND the verb form is given, the expected answer is Past Perfect for the earlier action when it is clearly prior.
✓ Both acceptable: After he had submitted the form, he left. ✓ / After he submitted the form, he left. ✓
✓ But: He had submitted the form before he left. — Past Perfect required for emphasis of sequence without “after/before” present.
NDA PYQConsecutive Actions — had + V3
Q14. (NDA 2025-II) Find the error: “(A) Hardly had / (B) he reached the base / (C) when he received fresh orders / (D) No error”
Answer: (D) No error This is correct. “Hardly had + subject + Past Participle + when + Simple Past” is the standard inversion structure for expressing that two events happened in very quick succession. The Past Perfect (“had reached”) + Simple Past (“received”) is the correct tense combination.
Q15. (NDA 2024-I) Find the error: “(A) After the CO / (B) gave the orders, / (C) the troops have deployed / (D) No error”
Answer: (C) Both actions are clearly in the past. The deploying happened after the orders — so it should be Simple Past, not Present Perfect. Correct: “the troops deployed”. Present Perfect “have deployed” is wrong because the action is completed in a clearly past context. Also acceptable: “had deployed” (Past Perfect for the later event after “after”).
Q16. (NDA 2023-I) Fill in the blank: “No sooner ___ the attack begun than reinforcements arrived.”
(a) has
(b) had
(c) was
(d) did
Answer: (b) had “No sooner…than” is a fixed inversion structure. After “no sooner” at the start of a sentence, inversion occurs: “No sooner had + subject + Past Participle + than + Simple Past”. The full correct sentence: No sooner had the attack begun than reinforcements arrived.
Q. Find all errors: “She is working here since two years and will join the new unit when she will get orders.”
Error 1: “is working since two years” → “since” requires a point in time, not a duration. Use “for”. And the tense must be Present Perfect Continuous (ongoing action with no past endpoint). Correct: “has been working for two years”. Error 2: “when she will get orders” → Time clause in future context: replace “will get” with Simple Present. Correct: “when she gets orders”. Corrected:She has been working here for two years and will join the new unit when she gets orders.
Q. Find all errors: “By the time the relief party will reach, the soldiers already waited for six hours.”
Error 1: “will reach” in the “by the time” clause → Future time clause uses Simple Present. Correct: “by the time the relief party reaches”. Error 2: “already waited for six hours” → The soldiers will still be waiting at the future point “when the relief party reaches”. Action started in past, ending at a future point → Future Perfect Continuous: “will have been waiting for six hours”. Corrected:By the time the relief party reaches, the soldiers will have been waiting for six hours.
Q. Find the error: “While the officer briefed the team, his radio has crackled and disrupted the briefing.”
Error 1: “briefed” → Briefing is the longer, ongoing background action (it was happening when the interruption occurred) → Past Continuous. Correct: “was briefing”. Error 2: “has crackled” → This is a sudden past event (not a present-connected event) → Simple Past. Correct: “crackled”. Corrected:While the officer was briefing the team, his radio crackled and disrupted the briefing.
📋 Quick Reference — Tense Signals at a Glance
▶ Simple Present
always, usually, often, generally
rarely, never, sometimes
every day/week/year, on Sundays
habitually, regularly
▶ Present Continuous
now, right now, at this moment
currently, at present, today (ongoing)
look! listen! (imperative trigger)
this week / this month (temporary)
▶ Present Perfect
just, already, yet, ever, never
recently, lately, so far, till now
since [point], for [duration]
NOT with: yesterday, last year, ago
▶ Simple Past
yesterday, last week/month/year
ago (three days ago, a year ago)
in [year]: in 2020, in 1947
that day, then, once, in those days
▶ Past Continuous
while (long background action)
when (= at that moment, background)
all day, all night, the whole morning
at that time, throughout
▶ Past Perfect (had + V3)
before, after, by the time (past)
hardly…when; no sooner…than
by [past time] (by noon, by then)
earlier of two past actions
▶ Simple Future
tomorrow, next week/month/year
soon, shortly, in a week, later
in the future, shortly
One “will” per sentence (main clause only)
▶ Future Perfect (will have + V3)
by tomorrow / by next week
by [future date] / by the time (future)
Action completed before a future point
▶ Since / For Framework
No end stated → has/have been + V-ing
Past end point → had been + V-ing
Future end point → will have been + V-ing
since = point; for = duration
⚠ One-Will Rule
when/if/unless/as soon as → Simple Present (not will)
This material is for personal NDA exam preparation only. Unauthorised reproduction or distribution is prohibited.
All rights reserved · ODEA.Classes@gmail.com · olivedefence.com