Choose the most suitable option to replace the highlighted part of the sentence:
No sooner had I reached the station when the train departed.

Correct option is A

The correct substitution of the highlighted words is (a) “than the train departed”.
Explanation:
· The correlative conjunction pair used with “No sooner” is “than”, not “when”.
· The structure No sooner + had + Subject + V3 + than + Subject + V2 shows that the second action happened immediately after the first action.
· Hence, “when” is grammatically incorrect here, and it must be replaced by “than” to make the sentence correct.
· Grammatical rule used:
· No sooner is followed by inversion (auxiliary before subject) in the first clause and is always paired with than in the second clause.
· Structure: No sooner + had + subject + past participle (V3) + than + subject + past tense (V2).
· Example:
· No sooner had the bell rung than the students ran out of the class.
· Information booster / exception:
· Similar pairs: Hardly/Scarcely + had + V3 + when (NOT than).
· Hardly had I reached home when it started raining.
· But: No sooner had I reached home than it started raining.