Sentence Improvement questions give you a sentence with one part underlined. Your job is to decide whether that part contains an error — and if so, pick the option that corrects it. One option is always "No improvement" (sometimes written as "No improvement required").
Think of it like this: the examiner has written a sentence with a deliberate grammatical fracture — a hairline crack. Your job is not to rewrite the sentence; it is to find that exact crack and patch it. The rest of the sentence is structurally sound.
Here is what separates this question type from Error Spotting: in Error Spotting, you identify which part of the sentence is wrong. In Sentence Improvement, the error location is already handed to you (the underline). Your job is purely about choosing the correct form from four options. That is actually an advantage — you can use the options to reverse-engineer which grammar rule is being tested, even before reading the sentence carefully.
The grammar areas that CGL repeats most consistently in this question type:
since, for, yet, already, when, whileneither...nor, along with, as well as, one of thesince vs. for, in vs. at vs. on, between vs. amongthat before question words, backshifting tenses, changing pronounswho for persons, which for things, that as a flexible alternative, whom after a prepositionno sooner...than, scarcely...when, neither...nor, either...or, not only...but alsoThe analogy that helps: treat these questions like a doctor checking an X-ray. You are not looking at the whole body — you are looking at the one spot the radiologist has circled. Your diagnostic vocabulary is grammar rules. A sharp doctor does not second-guess the whole scan; they apply specific knowledge to the marked region.
This is the single most frequently tested area. The key insight is that certain time expressions are locked to certain tenses — they are not interchangeable.
since vs. for
since = specific point in time → since 2015, since Monday, since childhoodfor = duration / period of time → for five years, for three hours, for a long timeThe tense that pairs with both is Present Perfect or Present Perfect Continuous:
She has lived here for ten years. (duration)She has lived here since 2015. (point in time)If you see since + a number (since five years), that is the error. Swap since with for.
is working vs. has been working with since
since demands a perfect tense because it signals an ongoing action that started in the past. Simple Present (is working) cannot pair with since. The correct form is Present Perfect Continuous (has been working) when the action is ongoing, or Present Perfect (has worked) when the result matters.
Other locked pairs to memorise:
| Time marker | Correct tense |
|---|---|
| since, for (with ongoing action) | Present Perfect / Present Perfect Continuous |
| yesterday, last year, ago | Simple Past |
| when + past event | Simple Past |
| while + background action | Past Continuous |
| by tomorrow, by next year | Future Perfect |
Neither...nor / Either...or / Not only...but also
The verb agrees with the subject closer to it (the one just before the verb). This is called the "proximity rule."
Neither the manager nor the employees were present. → employees is plural → wereNeither the employees nor the manager was present. → manager is singular → wasAlong with, as well as, together with, in addition to
These are not conjunctions — they are parenthetical phrases. They do not change the number of the main subject. The verb agrees with the grammatical subject only.
The teacher along with her students was going. → Main subject = The teacher (singular) → wasThink of along with her students as information inside invisible brackets. Strip it out: The teacher _____ going. → was.
One of the + plural noun + who/which + plural verb
He is one of the best students who have ever studied here.Here, the relative clause who have ever studied refers to students (plural), not to he. So the verb is plural. This one trips people up constantly.
When converting direct speech to indirect speech:
Rule 1: No that before a question word.
You cannot write asked that why. It is always asked why. The question word itself does the connecting job; that is redundant and wrong.
Rule 2: The word order in the embedded question is statement order (Subject + Verb), not question order (Verb + Subject).
asked why were they making noiseasked why they were making noiseRule 3: Tense backshifts.
He said, "I am tired." → He said that he was tired.| Pronoun | Used for |
|---|---|
| who | Person (subject) |
| whom | Person (object) |
| whose | Person / thing (possession) |
| which | Things / animals |
| that | Persons or things (in defining clauses) |
which for a person is always an error in SSC-level sentences. Swap it to who or whom.
These are fixed pairs. Memorise them as units:
No sooner...than (not then, not when)Scarcely/Hardly...when/before (not than)Neither...norEither...orNot only...but alsoBoth...andWhen you see since or for underlined, ask: is what follows a point in time or a period of time? Point → since. Period → for. This check takes under 3 seconds. Cross-map it to the tense: if the verb is Simple Present with since, that is a double error (fix both). Standard method: re-read the whole grammar rule (~40s of recall). This pattern: ~5 seconds of scanning the noun after the preposition.
For along with / as well as / together with constructions, mentally bracket the middle phrase and read the sentence without it. The teacher [along with her students] ___ going. Now agreement is obvious: The teacher was going. No more confusion about plural nouns nearby. Standard method: students often count all nouns in the sentence (~30s, high error rate). This bracket method: ~8 seconds, almost zero errors.
In reported speech, if you see asked that why or told that where, the fix is immediate — delete that. Question words (why, where, when, how, what, which) never co-exist with that in indirect speech. Check for this in 2 seconds by scanning for [verb] + that + [question word]. If that pattern exists, that must go. Saves you 20+ seconds of mentally reconstructing the full indirect speech rule.
Cover the first subject completely. Read only: nor/or [second subject] [verb]. Does the verb match the second subject's number? If yes, the sentence is correct. If not, fix the verb to match. Example: Neither the boys nor the captain ___ ready. Cover Neither the boys — you see nor the captain [verb]. Captain = singular → was. Standard method: students debate both subjects (~25s). Proximity test: ~6 seconds.
Before reading the sentence in depth, glance at the four options. If three options differ only in tense (was / were / has been / No improvement), the question tests subject-verb agreement or tense. If three options differ in prepositions (since / for / from / during), it tests preposition logic. This pre-scan primes your brain for the specific rule, so when you read the underlined part, you know exactly what to look for. Saves 10-15 seconds of open-ended analysis per question.
When you land on a Sentence Improvement question in the exam hall, run this decision tree:
Step 1 — Option Scan (3 seconds). What do the three non-"No improvement" options have in common? Identify the grammar area being tested (tense / agreement / preposition / pronoun / conjunction).
Step 2 — Underline Analysis (5-8 seconds). Read only the underlined part, then read 3-4 words before and after it for context. Rarely do you need the full sentence.
Step 3 — Apply the Single Rule. You have already identified the grammar area in Step 1. Apply that rule directly. You are not doing a full grammar audit — you are checking one specific thing.
Step 4 — Eliminate. Cross out options that violate the rule. Usually two options are obviously wrong.
Step 5 — "No improvement" check. Only pick "No improvement" after you have genuinely checked the underlined part and found nothing wrong — not because you are unsure. If you are unsure, the answer is rarely "No improvement" in CGL; most questions do have an error.
Target time per question: under 45 seconds.
Why this question: This is the foundational since vs. for question — appears in almost every CGL session. Getting this right in 10 seconds is the goal.
Solving path: Underlined part: since five years. Ask — is five years a point in time or a duration? Duration. So since is wrong; for is correct. Eliminate option A (from five years — from is not used with perfect tenses in this context), eliminate option C (No improvement — there is a clear error), eliminate option D (by five years — by signals deadline, not duration). Answer: B (for five years). Time: ~12 seconds.
Why this question: Reported speech + question word is a classic CGL trap. The that + why combination catches unprepared candidates every time.
Solving path: Underlined part: that why they were making noise. Scan: question word why is present after that. Rule: that cannot precede a question word in reported speech. So that must be dropped. Check word order: why they were making noise — subject (they) before verb (were making) — correct statement order. Answer: C (why they were making noise). Eliminate A (why were they — question order, wrong), eliminate D (that why are they — wrong on two counts). Time: ~18 seconds.
Why this question: Tests the since → Present Perfect Continuous tense lock. Many students pick "No improvement" here because they do not flag is working as wrong.
Solving path: The sentence says since 2015 — that means the action started in 2015 and is still ongoing now. is working (Simple Present) cannot pair with since for an ongoing past action. You need Present Perfect Continuous: has been working. Option B (is been working) is not a valid tense form. Answer: D (has been working). Time: ~15 seconds.
Why this question: Tests the proximity rule in neither...nor. This is the most common subject-verb agreement trap in CGL.
Solving path: Apply the proximity test. Cover Neither the manager — read: nor the employees [verb] present. employees = plural → verb must be plural → were. Underlined was is wrong. Answer: A (were). Eliminate B (are — wrong tense; past context required) and C (is — singular, still wrong). Time: ~10 seconds.
Why this question: The along with trap — candidates see students and jump to a plural verb. This question is designed to catch that reflex.
Solving path: Bracket out the middle: The teacher [along with her students] ___ going. Grammatical subject = The teacher (singular) → verb must be singular → was. Underlined were is wrong. Answer: A (was). Answer B (are) is present tense, wrong context. Answer D (have been) is perfect tense, wrong here. Time: ~10 seconds.
Why this question: Idiomatic correlative pairs are tested frequently, and No improvement is the correct answer — a good reminder not to second-guess correct sentences.
Solving path: Underlined word: than. Recognize the correlative: No sooner...than. This is the fixed idiomatic pair. when, then, and but are all incorrect partners for no sooner. The sentence as written is correct. Answer: B (No improvement). Time: ~8 seconds.
Picking "No improvement" when unsure. This is not a safe default. If you genuinely cannot identify the error, use elimination — two or three options are usually clearly wrong, and that narrows your choice considerably. "No improvement" as a guess wastes the advantage the format gives you.
Confusing since + duration with since + point in time. Candidates write since five years all the time in their own writing (influenced by Hindi — "पाँच साल से"). That muscle memory is the enemy. Whenever you see since + [number] + [unit of time], flag it immediately as an error and replace with for.
Applying question word order in reported speech. In direct speech: "Why are they making noise?" — verb before subject. In reported speech: asked why they were making noise — subject before verb. Candidates who hear the sentence in their head often revert to question order. Write it out or consciously flip it.
Treating along with as a conjunction. Along with, as well as, in addition to are prepositions/adverbial phrases, not conjunctions like and. They do not add a second subject. The verb always agrees with the main subject before them.
Using which for people. which for persons is always wrong at SSC level. If the antecedent is a person, the relative pronoun is who (subject) or whom (object). Do not let that confuse you here — that is acceptable for persons in defining clauses, but which is not.
Ignoring the tense of the surrounding sentence when correcting the underlined verb. Candidates sometimes pick a tense that is grammatically valid in isolation but clashes with the time markers in the sentence. Always read 3-4 words before and after the underline — specifically look for time markers (yesterday, since, when, already, by, while) before committing to a tense.