Question

As soon as Sania sat down to study, the lights went off.

(Begin: No sooner ________)

Answer 1

Hint: The expression ‘No sooner’ is used when the sentence suggests that one action or situation took/takes place right after some other action or situation.

Complete step-by-step answer:

‘No sooner’ is the negative form of ‘As soon as’.
This expression is accompanied by the conjunction ‘that’ after the first half of the sentence.
When the expression ‘No sooner’ comes at the beginning of a sentence, we use inverted word order of sentence starting with ‘As soon as’. This means that the auxiliary verb comes before the subject.
An auxiliary verb or a helping verb is used along with the main verb to help express the main verb's tense, mood, or voice, for example- is, have, will do.
The main verb in this sentence is ‘sat’. The right auxiliary verb to go along with ‘sat’ would be ‘did’. However, after using ‘did’, the main verb shall change its tense to present since there can be only one verb with past tense in a given sentence.
Therefore, the correct answer will be:
No sooner did Sania sit down to study than the lights went off.

Note: Do not mistake this question for an active/passive voice question, as this question only involves using the negative form of the expression ‘As soon as’ and then reordering it in an inverted form.