CDS English · Spotting Errors
Tenses: match the verb to the time
The second check on every sentence: does each verb show the right time? A time word or another verb in the same sentence nearly always tells you which tense is correct.
Why this matters
Tense items give their clue inside the sentence: 'Look!', 'yesterday', 'for three hours', 'so far', or a past verb such as 'asked' or 'said'. Find the clue first and the correct tense follows. The verb with the wrong tense and the clue are often in different parts, so read the whole sentence before you mark.
Concept 1 of 4: Simple vs continuous, and stative verbs (own, think, know)
An English verb shows two things: the time (past, present, future) and the shape of the action. Is it a plain fact, an action still in progress, or an action already complete? 'I write' is a habit. 'I am writing' is happening now. Some verbs describe a state, not an action. They almost never take the -ing form.
Definition
- A tense is built from auxiliaries (helping verbs: be, have, do, will) plus the main verb.
- Simple (I play, I played): a fact, a habit or a general truth.
- Continuous (be + -ing: I am playing): an action in progress at one moment. Clues: Look!, Listen!, now, at the moment, a change happening as you speak ('It is getting dark').
- Perfect (have + the third form of the verb, its past participle: I have played): an action complete by some point of time.
- Perfect continuous (have been + -ing): an action that began in the past and is still going on, with a length of time: for three hours, since morning.
- Stative verbs describe a state: own, possess, belong, know, understand, believe, think (when it means 'believe'), like, love, want, need, seem, contain. Use them in the simple form: 'I know him', not 'I am knowing him'.
| Clue in the sentence | Tense needed | Correct example | Tested in |
|---|---|---|---|
| Look! or Listen! | Present continuous | Look! The bus is coming. | 2021 (II)Q |
| A change happening as you speak | Present continuous | It is getting cold; shall I close the window? | 2021 (II)Q |
| for + a length of time, still going on | Present perfect continuous | She has been studying for two hours. | 2021 (II)Q |
| think meaning 'believe' | Simple present | My father thinks I work too hard. | 2022 (I)Q |
| own, possess, belong | Simple present | This land belongs to the state. | 2024 (II)Q |
Other stative verbs to watch: know, understand, believe, prefer, mean, consist, contain, seem.
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2024 · CDS (II) 2024 — English · Q76Moderate
Example 1 · Spotting Errors · Tenses and Sequence of Tenses
Directions: find the error in an underlined part, else No error
I am owning two houses in Bengaluru.
'Think' has two meanings
'I am thinking about the test' is correct: here 'think' means 'consider', an action. 'I am thinking you are right' is wrong: here it means 'believe', a state. Ask which meaning the sentence uses.
A duration still running needs 'have been + -ing'
When a sentence gives a length of time (for three hours, since morning) for an action that is still going on, the exam wants the perfect continuous: 'I have been playing for three hours'.
Simple present is not for 'right now'
After 'Look!' or 'Listen!', or for a change happening as you speak ('It begins to turn dark'), the simple present is wrong. Use be + -ing: 'It is beginning to turn dark'.
Concept 2 of 4: Present perfect vs simple past: the time marker decides
The present perfect (has gone, have seen) joins the past to now. The simple past (went, saw) closes the action at a finished time. So a word that names a finished time, such as 'yesterday', rules out the present perfect.
Definition
- A time marker is a word or phrase that fixes when the action happens.
- Finished-time markers take the simple past: yesterday, last week, in 2015, two days ago, and a 'when' clause about the past ('When she heard the news, she was pleased').
- Up-to-now markers take the present perfect: so far, yet, already, ever, since, recently, just, this week, today (while today is still going on).
- Never use has/have + past participle with a finished-time marker: 'I have seen him yesterday' is wrong.
- Two linked clauses about the same time keep the same time: 'The project is going well; we haven't faced any delays.'
Worked example
Find the part with the error. (a) The train (b) has left the station (c) ten minutes ago. (d) No error
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2021 · CDS (II) 2021 — English · Q22Moderate
Example 2 · Spotting Errors · Tenses and Sequence of Tenses
Directions: find the error in three underlined parts or no error
Lavanya hasn't gone to work yesterday.
Mark the verb, not the time word
The time marker ('yesterday', 'ago') is usually correct. The wrong word is the verb that clashes with it, and it often sits in a different part.
'Today' can take more than one tense
'I have had two cups of tea today' (the day is still going on) and 'I had a good lunch today' (the lunch is over) are both correct. What is wrong is the simple present for a single event that has already happened: 'The students have a good time today' needs 'had' or 'have had'.
A past 'when' clause is a finished time
'When she heard the news, she hasn't been pleased' is wrong. The 'when' clause fixes a past moment, so the main verb is simple past: 'she wasn't pleased'.
Concept 3 of 4: Sequence of tenses: past perfect, reported clauses, keeping one time frame
When a sentence is about the past, its verbs should stay in the past. If one past action happened before another, the earlier one goes one step further back: had + past participle.
Definition
- The past perfect (had + past participle) marks the earlier of two past actions: 'The train had left before we reached the station.'
- A reporting verb (said, asked, told, thought, knew) passes on someone's words. This is reported speech. When the reporting verb is past, the reported clause moves into the past too: will becomes would, can becomes could, is becomes was, has done becomes had done.
- Exception: a universal truth stays in the present: 'The teacher said that the earth moves round the sun.'
- Keep one time frame: two verbs that share a subject, or are joined by 'and', take the same tense ('it produces ... and consumes ...').
- In a contrast, the second clause repeats the first clause's helper: 'Some could swim, while others couldn't.'
Worked example
Find the part with the error. (a) By the time the fire brigade arrived, (b) the house burnt (c) to the ground. (d) No error
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2018 · CDS (I) 2018 — English · Q80Moderate
Example 3 · Spotting Errors · Tenses and Sequence of Tenses
Directions: find error in underlined part a/b/c or no error
I asked him what he has done.
Universal truths do not shift
After 'said' or 'taught', a fact that is always true keeps the present tense: 'He taught us that honesty is the best policy.' Do not push it into the past.
'Had' needs a second past action
Use the past perfect only when one past action came before another. 'I had gone to Delhi last year', with no second action, should be 'I went to Delhi last year'.
Match the helper in a contrast
'Some people could write well, while others didn't' mixes two helpers. The second clause repeats the first: 'while others couldn't'.
A general statement keeps every verb in the present
If a sentence states a general truth in the present ('Our greatest glory is ...'), a past verb later in it is the error: 'rising every time we fall', not 'we fell'.
Concept 4 of 4: Conditionals and the subjunctive (If I were, had + V3, recommend that he go)
An 'if' sentence has two halves: the condition and the result. Each kind of condition has a fixed pair of tenses. Learn the pairs, then check that the two halves match.
Definition
- A conditional is a sentence with an 'if' clause and a result clause.
- Real future: If + present, will + verb. 'If it rains, we will stay in.'
- Unreal present (second conditional): If + past, would + verb. With 'be', use were for every subject: 'If I were you, I would ...'.
- Unreal past (third conditional): If + had + past participle, would have + past participle. 'If you had asked, I would have helped.'
- Never put 'would' in the if-clause. 'If he would have come' is wrong; say 'If he had come'.
- The subjunctive: after recommend, suggest, insist, demand, propose + that, use the plain dictionary form of the verb for every subject: 'I suggest that he leave early', not 'he leaves' or 'he would leave'. ('He should leave' is also accepted.)
| Pattern | Correct form | Wrong forms the exam prints | Tested in |
|---|---|---|---|
| Unreal past (third conditional) | If you had checked, you would have known. | If you have checked ... / If you would have checked ... | 2017 (II), 2020 (I)Q |
| Unreal present with 'be' | If I were in his place, I would refuse. | If I was in his place ... / If I am in his place ... | 2017 (II), 2022 (I)Q |
| recommend / suggest / insist + that | The doctor suggested that she rest. | that she would rest / that she rests | 2026 (II)Q |
Read both halves before you judge the 'if' part: the result clause tells you which pair you need.
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2017 · CDS (II) 2017 — English · Q92Moderate
Example 4 · Spotting Errors · Tenses and Sequence of Tenses
Directions: find error in part a, b or c; else no error
If you have thought about the alternatives, you would not have chosen such a difficult topic for the term paper.
No 'would' in the if-clause
'Would' belongs in the result half only. 'If the plan would have worked ...' is always wrong; the if-half takes 'had worked'.
'Were' for every person
You will hear 'If I was you' in speech. In this exam the answer is 'If I were you', and the same for he, she and it.
Match the two halves
'Would have + past participle' in the result needs 'had + past participle' in the if-clause. 'If she has known, she would have helped' has the wrong pair: the result is right, so the error is in the if-part ('If she had known').
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Reference tables (2)
Simple vs continuous, and stative verbs (own, think, know)5 rows
| Clue in the sentence | Tense needed | Correct example | Tested in |
|---|---|---|---|
| Look! or Listen! | Present continuous | Look! The bus is coming. | 2021 (II)Q |
| A change happening as you speak | Present continuous | It is getting cold; shall I close the window? | 2021 (II)Q |
| for + a length of time, still going on | Present perfect continuous | She has been studying for two hours. | 2021 (II)Q |
| think meaning 'believe' | Simple present | My father thinks I work too hard. | 2022 (I)Q |
| own, possess, belong | Simple present | This land belongs to the state. | 2024 (II)Q |
Other stative verbs to watch: know, understand, believe, prefer, mean, consist, contain, seem.
Conditionals and the subjunctive (If I were, had + V3, recommend that he go)3 rows
| Pattern | Correct form | Wrong forms the exam prints | Tested in |
|---|---|---|---|
| Unreal past (third conditional) | If you had checked, you would have known. | If you have checked ... / If you would have checked ... | 2017 (II), 2020 (I)Q |
| Unreal present with 'be' | If I were in his place, I would refuse. | If I was in his place ... / If I am in his place ... | 2017 (II), 2022 (I)Q |
| recommend / suggest / insist + that | The doctor suggested that she rest. | that she would rest / that she rests | 2026 (II)Q |
Read both halves before you judge the 'if' part: the result clause tells you which pair you need.
Watch out for (13)
- 'Think' has two meanings→ Simple vs continuous, and stative verbs (own, think, know)
- A duration still running needs 'have been + -ing'→ Simple vs continuous, and stative verbs (own, think, know)
- Simple present is not for 'right now'→ Simple vs continuous, and stative verbs (own, think, know)
- Mark the verb, not the time word→ Present perfect vs simple past: the time marker decides
- 'Today' can take more than one tense→ Present perfect vs simple past: the time marker decides
- A past 'when' clause is a finished time→ Present perfect vs simple past: the time marker decides
- Universal truths do not shift→ Sequence of tenses: past perfect, reported clauses, keeping one time frame
- 'Had' needs a second past action→ Sequence of tenses: past perfect, reported clauses, keeping one time frame
- Match the helper in a contrast→ Sequence of tenses: past perfect, reported clauses, keeping one time frame
- A general statement keeps every verb in the present→ Sequence of tenses: past perfect, reported clauses, keeping one time frame
- No 'would' in the if-clause→ Conditionals and the subjunctive (If I were, had + V3, recommend that he go)
- 'Were' for every person→ Conditionals and the subjunctive (If I were, had + V3, recommend that he go)
- Match the two halves→ Conditionals and the subjunctive (If I were, had + V3, recommend that he go)
Test yourself on Spotting Errors
25 past CDS questions from this chapter, timed at 25 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.