Q1. Complete the sentence by choosing the most appropriate preposition from the options given below: I reached the school _______ the gates closed.
A later
B before Correct
C by
D from
Explanation
The sentence needs a word that shows the time relation between reaching the school and the gates closing. Before correctly means that the speaker reached the school earlier than the closing of the gates. Later is an adverb and would require a different structure, such as "later than". By can mark a deadline before a noun phrase, but "by the gates closed" is not grammatical. From marks a starting point, so it does not fit the time-clause meaning required here.