Error Detection & Sentence Improvement: The 5 Rules That Crack Every Bank Exam
A fast, exam-focused guide to the five grammar rules — subject-verb agreement, tense, prepositions, articles and parallelism — that power almost every Error Detection and Sentence Improvement question in IBPS and SBI PO/Clerk exams, with a 4-step attack method and two fully worked examples.
By the PadhoDost Team · 📖 6 min read · Updated 4 August 2026
Part of Banking (IBPS / SBI) prep🧠 Spot the odd one out
Picture a big family wedding photo. Everyone is dressed in bright ethnic wear, and then one cousin turns up in a T-shirt and shorts. Your eye catches him instantly, right? Error Detection works exactly like that. The sentence is the photo; your job is to spot the one word that is 'wearing the wrong clothes'. Once you train your eye on a few fixed rules, wrong grammar starts jumping out at you just as fast.
Padho, dost! Error Detection and Sentence Improvement are twins. In both, the examiner shows you a sentence and asks: is the grammar clean, and if not, what fixes it? Together these topics quietly hand you 5-10 easy marks in almost every IBPS and SBI Prelims and Mains paper. The best part? You don't need a huge vocabulary. You need about five grammar rules, applied fast and calmly. Let's make them yours.
The two question types you will see
Error Detection: a sentence is broken into 4-5 parts — (a), (b), (c), (d) and (e). You choose the part that has the mistake. If everything is correct, the answer is 'No error'. Sentence Improvement: one part of the sentence is in bold or underlined, and you pick the option that replaces it best. If the bold part is already fine, you choose 'No improvement'. Different wrapping, same skill inside: knowing which grammar rule is being tested.
The 5 rules that crack ~80% of questions
| Rule | What to check | Wrong ✗ | Right ✓ |
|---|---|---|---|
| Subject–Verb Agreement | A singular subject takes a singular verb | The list of items are ready | The list of items is ready |
| Tense | Keep tenses consistent; no illegal jumps | He said he will come | He said he would come |
| Prepositions | Fixed word-pairs (in / on / at / to / for) | She is married with a doctor | She is married to a doctor |
| Articles | a / an / the — sound, first mention, uniqueness | He is honest man | He is an honest man |
| Parallelism | Items in a list share the same form | Reading, writing and to sing | Reading, writing and singing |
A few high-frequency sub-rules the examiners love: collective nouns (team, committee, jury, family) usually take a singular verb. 'Each, every, one of, either, neither' (used alone) take a singular verb. 'A number of students' is plural, but 'The number of students' is singular. With 'either...or / neither...nor', the verb follows the NEARER subject (the proximity rule). And for tense: 'since' pulls the present perfect ('I have known him since 2010'), while 'ago' pulls the simple past ('I met him two years ago').
Your 4-step attack method (under 30 seconds per question)
- 1Read the whole sentence once, fully, before staring at the parts — meaning comes first, grammar second.
- 2Find the real subject and its main verb, and mentally cross out any phrase sitting between them.
- 3Run the 5-rule scan in order: Agreement, Tense, Preposition, Article, Parallelism. Stop at the first rule that breaks.
- 4If nothing breaks a rule, be brave — choose 'No error' / 'No improvement'. Do not invent a mistake that isn't there.
📝 Worked example — Error Detection
Sentence: One of the students (a) / who scored well (b) / in the exam (c) / have been selected for the interview (d). No error (e)
Step 1 – Find the subject: it is 'One', not 'students'. The words 'of the students' are just a phrase describing 'One'.
Step 2 – 'One' is singular, so it needs a singular verb.
Step 3 – The verb 'have been selected' is plural. That is the mismatch.
Correction: 'has been selected'.
Answer: Part (d) has the error.
📝 Worked example — Sentence Improvement
Sentence: She is good at singing, dancing and TO PAINT.
The bold part to test: 'and to paint'.
Step 1 – Look at the list: singing, dancing, ___ . The first two are -ing forms (gerunds).
Step 2 – Parallelism rule: every item in a list must wear the same grammatical form.
Step 3 – 'to paint' (an infinitive) breaks the pattern.
Options: (a) and painting (b) and paints (c) and to painting (d) No improvement.
Answer: (a) 'and painting' — it matches singing and dancing.
60-second revision before the exam
- ✓Verb agrees with the subject, not the nearest noun — delete the middle phrase.
- ✓Collective nouns and 'one of / each / every / either / neither' → singular verb.
- ✓'Neither...nor / either...or' → verb follows the nearer subject (proximity rule).
- ✓'Since' → present perfect; 'ago' → simple past; don't shift tenses without reason.
- ✓Learn preposition pairs by heart (married to, superior to, capable of, comply with).
- ✓'A' before consonant sounds, 'an' before vowel sounds — go by SOUND (an hour, a university).
- ✓Lists must be parallel — all gerunds, all infinitives, or all nouns.
- ✓No rule broken? Confidently pick 'No error' / 'No improvement'.
⚡ Quick check
Find the part that contains an error: 'Neither the captain (a) / nor the players (b) / were aware of (c) / the new rule (d).' No error (e)
Ready to test yourself? 🎯
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