CDS English · Spotting Errors
No error: proving a sentence is correct
How to choose option (d) No error with confidence: run every part of the sentence through a fixed checklist, and pick (d) only when every check passes.
Why this matters
'No error' is the right answer on roughly one CDS spotting-errors item in six, but some papers have none at all, so it is neither rare nor a safe guess. The sentences are often short and plain, which tempts you to hunt for a hidden fault, and a few look wrong but are right. This page turns each rule into a check you can run in seconds.
Concept 1 of 4: Agreement and pronoun checks
The first check on any sentence is subject-verb agreement: a singular subject takes a singular verb, a plural subject a plural verb. The agreement page teaches it in full. Here the point is the reverse: some subjects look as if they break the rule but do not. Learn those, so you do not mark a correct sentence wrong.
Definition
Agreement checks (a sentence that passes all of them is fine on agreement):
- Match each verb to its head noun, not the nearest noun.
- Latin and Greek plurals are plural: memoranda, criteria, phenomena, media. 'The memoranda are ...' is right.
- Two nouns under one 'my' or 'the' that name one person take a singular verb: 'My friend and benefactor has come.'
- either ... or / neither ... nor: the verb agrees with the nearer subject: 'Either you or he is ...'.
- A collective noun (group, team, committee) acting as one unit is singular: 'A group of tourists has arrived.'
- A what-clause as subject is singular: 'What students need is practice.'
Pronoun checks:
- A relative pronoun joins a describing clause to a noun: who for people, which for things and animals, that for either.
- Name the subject once. 'A man who has lived here he will ...' gives the verb two subjects; drop 'he'.
Worked example
Find the part with the error. (a) Bread and butter (b) is (c) my usual breakfast. (d) No error
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2023 · CDS (I) 2023 — English · Q43Moderate
Example 1 · Spotting Errors · No Error (Correct Sentence)
Directions: find the error in the underlined parts or no error
Either he or I am mistaken.
A sentence can sound odd and still be right
'Either he or I am mistaken' sounds strange, because 'am' follows two people. But the verb agrees with the nearer subject, 'I', so it is correct. Test the rule; do not trust the sound.
'Which' for a person
'Our gardener, which is very lazy' is an error, even though the rest of the sentence is fine. Check every 'which' and 'who': is the noun before it a person or a thing?
A subject said twice
When a long 'who' clause separates the subject from its verb, a pronoun sometimes creeps in: 'a man who has lived here for years he will never ...'. The verb already has its subject. The extra 'he' is the error.
Short sentences invite over-thinking
'All of them speak good English' and 'Their belongings were lost in the fire' are simply correct. If every check passes, choose (d) and move on; inventing an error costs a third of a mark.
Concept 2 of 4: Tense checks against the time marker
A time marker is a word or phrase that fixes when something happens: today, a few years ago, for twenty years, when he was interviewed. Each marker allows only certain tenses. Find the marker, then check that the verb fits it. If it fits, the tense is fine.
Definition
Match the verb to the marker:
- today, now, these days → present: 'Today she is a singer.'
- ago, yesterday, last year, in 2010 → simple past: 'I went there a few years ago.' Never the present perfect.
- for / since + a period reaching up to now → present perfect: 'They have been married for twenty years.'
- An action already in progress when another past event happened → past continuous: 'He was suffering from fever when he was interviewed.'
- Past perfect (had + past participle) needs a later past point to be 'before': 'She had left when I arrived.'
- Two past actions told in order both take the simple past: 'She had a book but didn't read it.'
Questions: asking someone's home or origin uses the simple present: 'Where do you come from?' 'Where are you coming from?' asks about today's journey.
Worked example
Find the part with the error. (a) I have known (b) Ravi (c) since we were at school. (d) No error
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2021 · CDS (II) 2021 — English · Q25Moderate
Example 2 · Spotting Errors · No Error (Correct Sentence)
Directions: find the error in three underlined parts or no error
Raman and Mitali have been married for twenty years.
'Today' with a past verb
'Today she was an accomplished singer' looks fine because the sentence also talks about her youth. But each verb answers to its own marker: 'today' needs 'is'; 'in her youth' allows 'had trained'.
Simple past for a state that was going on
If an illness, a job or an activity was already going on when something else happened, use the past continuous: 'was suffering', 'was working'. The simple past makes it sound like a single finished event.
Where do you come from?
'Where are you coming from?' is correct English for a journey ('from the market'). When the next sentence asks about nationality, the question is about origin, and English uses 'Where do you come from?'.
Past perfect with nothing after it
The past perfect means 'before another past moment'. If the sentence names no later past moment, the simple past is usually what is needed.
Concept 3 of 4: Word, idiom and determiner checks
Some correct sentences contain an idiom that sounds silly, a rare word, or a fixed phrase that looks like a mistake. These are the items where students most often reject a correct sentence. Know the expressions below, and you will recognise them as correct.
Definition
What to check, and what is correct:
- An idiom is a fixed phrase whose meaning is not the sum of its words: 'raining cats and dogs' = raining very heavily. If it is in its standard form, it is correct.
- A rare word is not an error. If it fits the meaning (quotidian = everyday), it is right.
- A determiner (another, each, one) sets the noun's form: 'another' + a singular noun; 'one ... one's own'.
- A modal (can, could, must) takes the base verb: 'couldn't find'.
- A reflexive pronoun (myself, herself) is right when the subject acts on itself: 'She forced herself to eat.'
| Correct expression | Why it is correct | Sitting |
|---|---|---|
| It was raining cats and dogs. | A standard idiom: raining very heavily | 2017 (I)Q |
| Tell him to take another photograph of the group. | 'another' + a singular noun | 2017 (I)Q |
| He couldn't find an answer. | A modal takes the base verb; 'an' before a vowel sound | 2017 (I)Q |
| Are you through with that newspaper? | 'through with' = finished with | 2017 (II)Q |
| It's no secret that the President wants a second term. | 'It's no secret that' = everyone knows that | 2018 (I)Q |
| The legendary hero laid down his precious life for our country. | 'lay down one's life' = die for a cause; past: laid down | 2018 (II)Q |
| India won by an innings and three runs. | The standard cricket result phrase | 2019 (I)Q |
| One must not boast of one's own success. | 'one' is followed by 'one's'; 'boast of' is the fixed partner | 2023 (I)Q |
| She forced herself to eat. | Reflexive pronoun: she acts on herself | 2024 (I)Q |
| In your quotidian life you wouldn't find an elephant in the supermarket. | 'quotidian' = everyday, ordinary | 2026 (II)Q |
Every sentence in this table was a 'No error' item: the right answer was (d).
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2018 · CDS (II) 2018 — English · Q43Moderate
Example 3 · Spotting Errors · No Error (Correct Sentence)
Directions: find the part with an error or no error
The legendary hero laid down his precious life for our country.
A silly-sounding idiom is still correct
'Raining cats and dogs', 'through with', 'it's no secret': none of these means what its words say, but each is standard English. Do not mark an idiom wrong because it is not literal.
Laid down his life is right
'Lay down' (to give up, put down) is a transitive verb, and its past is 'laid'. A hero laid down his life. Do not confuse it with 'lie down' (rest), whose past is 'lay'.
A rare word is not a wrong word
If you do not know a word, you cannot use it as evidence of an error. Check the grammar around it; if that passes, the word is probably right.
Concept 4 of 4: Preposition, connector and comparison checks
The last checks cover the small words that join things: prepositions, linking words and comparisons. Each has a fixed form, taught on the earlier pages of this chapter. On a 'No error' item they all pass. Run them quickly and in order, and trust the result.
Definition
The final checks:
- Preposition: does each preposition match the word before it? waited for, dream of, agree with an idea, succeed in. A verb such as 'emphasise' takes no preposition at all.
- -ing after a preposition: a verb after a preposition is in the -ing form: dreamed of being, by putting.
- Connector: does the linking word give the right relation? 'so' for a result, 'unless' (= if not) with a positive verb, 'after which' to continue.
- Comparison: are both sides of the comparison the same kind of thing? 'likes Geography more than he likes History'.
- Lists: are all the items in the same form? buy, pick up and prepare.
If all of these pass, and the agreement, tense and word checks passed too, choose (d) No error.
Worked example
Find the part with the error. (a) He succeeded (b) in climbing the peak (c) before the storm arrived. (d) No error
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
CDS · 2026 · CDS (II) 2026 — English · Q48Hard
Example 4 · Spotting Errors · No Error (Correct Sentence)
Directions: Each item in this section has a sentence with three underlined parts labelled (a), (b) and (c). Read each sentence to determine whether there is an error in any underlined part and indicate your response on the answer sheet against the above-mentioned corresponding letter. If there is no error, indicate your response as (d).
I often dreamed of being famous in my prime.
A correct preposition can look wrong
'I don't agree with smacking children' is right: you agree with an idea or an action, and agree to a proposal. Check the pair against what you know, not against how often you have heard it.
'Unless' with a positive verb is correct
'Children are not allowed in unless they are with an adult' is right. 'Unless' already carries the 'not', so the verb after it stays positive.
'Emphasise the need for' has no extra preposition
'Emphasised the need for strict discipline' is right: the 'for' belongs to 'need', not to 'emphasise'. Do not mistake it for the error 'emphasised on'.
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 (1)
Word, idiom and determiner checks10 rows
| Correct expression | Why it is correct | Sitting |
|---|---|---|
| It was raining cats and dogs. | A standard idiom: raining very heavily | 2017 (I)Q |
| Tell him to take another photograph of the group. | 'another' + a singular noun | 2017 (I)Q |
| He couldn't find an answer. | A modal takes the base verb; 'an' before a vowel sound | 2017 (I)Q |
| Are you through with that newspaper? | 'through with' = finished with | 2017 (II)Q |
| It's no secret that the President wants a second term. | 'It's no secret that' = everyone knows that | 2018 (I)Q |
| The legendary hero laid down his precious life for our country. | 'lay down one's life' = die for a cause; past: laid down | 2018 (II)Q |
| India won by an innings and three runs. | The standard cricket result phrase | 2019 (I)Q |
| One must not boast of one's own success. | 'one' is followed by 'one's'; 'boast of' is the fixed partner | 2023 (I)Q |
| She forced herself to eat. | Reflexive pronoun: she acts on herself | 2024 (I)Q |
| In your quotidian life you wouldn't find an elephant in the supermarket. | 'quotidian' = everyday, ordinary | 2026 (II)Q |
Every sentence in this table was a 'No error' item: the right answer was (d).
Watch out for (14)
- A sentence can sound odd and still be right→ Agreement and pronoun checks
- 'Which' for a person→ Agreement and pronoun checks
- A subject said twice→ Agreement and pronoun checks
- Short sentences invite over-thinking→ Agreement and pronoun checks
- 'Today' with a past verb→ Tense checks against the time marker
- Simple past for a state that was going on→ Tense checks against the time marker
- Where do you come from?→ Tense checks against the time marker
- Past perfect with nothing after it→ Tense checks against the time marker
- A silly-sounding idiom is still correct→ Word, idiom and determiner checks
- Laid down his life is right→ Word, idiom and determiner checks
- A rare word is not a wrong word→ Word, idiom and determiner checks
- A correct preposition can look wrong→ Preposition, connector and comparison checks
- 'Unless' with a positive verb is correct→ Preposition, connector and comparison checks
- 'Emphasise the need for' has no extra preposition→ Preposition, connector and comparison checks
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.