Question

Fill in the blank with the most appropriate prepositions:
I have been waiting ___ four o'clock.

• A. Ever
• B. Since
• C. For
• D. At

Answer 1

Answer: (B)

Since

Here, 'since' is correct because it implies from a time in the past until a later past time, or until now, here it is four o'clock.
'Ever' is incorrect because it is used in negative sentences and questions, or sentences with if to mean ‘at any time’.
'For' is incorrect because it is used to show who is intended to have or use something or where something is intended to be put.
'At' is incorrect because it is used to say where something/somebody is or where something happens.