It was him who solved the puzzle first. (Improve)

• A. It was he who (Answer)
• B. It was his who
• C. It was himself who
• D. No improvement

In the cleft construction 'It was ___ who...', the pronoun functions as the subject of the relative clause and must be in the subjective case: 'It was he who'. 'Him' is common in speech but incorrect in formal writing.

Never I have seen such a beautiful sunset. (Improve)

• A. Never have I seen (Answer)
• B. Never I saw
• C. Never did I have seen
• D. No improvement

When a negative adverb ('never', 'rarely', 'seldom') begins a sentence, subject-auxiliary inversion is required: 'Never have I seen'. Placing the subject before the auxiliary is incorrect.

Only after the exam I realised my mistake. (Improve)

• A. did I realise my mistake (Answer)
• B. I did realise my mistake
• C. I had realised my mistake
• D. No improvement

The fronted restrictive adverbial 'Only after the exam' triggers subject-auxiliary inversion in the main clause: 'did I realise my mistake', not normal word order.

It is the students who is responsible for the mess in the classroom. (Improve)

• A. who are responsible (Answer)
• B. who was responsible
• C. who has been responsible
• D. No improvement

In the cleft sentence 'It is the students who...', the verb in the relative clause must agree with 'students' (plural), not with 'it'. Correct: 'who are responsible'.

Hardly he had reached the station when the train left. (Improve)

• A. Hardly had he reached (Answer)
• B. Hardly he reached
• C. Hardly did he reach
• D. No improvement

'Hardly', like 'scarcely' and 'no sooner', requires subject-auxiliary inversion when placed at the start of a sentence: 'Hardly had he reached the station'.

Not until the results were declared did the students relax. (Improve)

• A. the students did relax
• B. the students relaxed did
• C. No improvement (Answer)
• D. did relax the students

The fronted negative adverbial 'Not until the results were declared' correctly triggers inversion in the main clause: 'did the students relax'. No improvement — tests whether students needlessly alter a correctly inverted sentence.

So beautiful was the view that we forgot to take pictures. (Improve)

• A. was so beautiful the view
• B. the view was so beautiful
• C. No improvement (Answer)
• D. beautiful was so the view

Fronting 'so + adjective' correctly triggers inversion: 'was the view'. This is a standard emphatic construction. No improvement — many students mistakenly 'correct' valid inversions back to normal word order.

It was not the manager but his assistant who were responsible for the delay. (Improve)

• A. who was responsible (Answer)
• B. who is responsible
• C. who has been responsible
• D. No improvement

In 'It was not X but Y who...', the relative clause verb agrees with Y — the element being affirmed. Since 'his assistant' (singular) is affirmed, not 'the manager', the verb must be singular: 'who was responsible'.

Little did she realise that her decision would changed her entire life. (Improve)

• A. would change (Answer)
• B. would changing
• C. will change
• D. No improvement

'Would' is a modal verb and must be followed by the bare infinitive: 'would change', not 'would changed'. The correct inversion 'Little did she realise' at the start is a decoy — the real error is the basic modal-verb slip at the end.

Rarely does one come across a leader as humble as him. (Improve)

• A. as humble as he (Answer)
• B. as humble as his
• C. as humble as himself
• D. No improvement

After 'as...as' or 'than' in a comparison, the pronoun should be in the subjective case when it stands for the implied subject of an elided clause: 'as humble as he [is]'. 'Him' is common in speech but marked as an error in formal grammar and competitive exams.