Question

we ---- by a loud noise during last night.

a-woke up
b-were woken up​

Answer 1

Answer:

We were woken up by a loud noise last night..

Answer 2

ANSWER:

We were woken up by a loud noise during last night.

EXPLANATION:

    In the given sentence the subject of the sentence did not do the action itself. Instead it was made to do the action by an external agent. The external agent is the loud noise.

    In such cases the sentence is written in passive voice and the verb is written in its participle form. Therefore option B "woken up" is the correct answer.