Question

Marry stamps ________ by me since last year.

1. A.
   are collected
2. B.
   were collected
3. C.
   have been collected
4. D.
   had been collected

Answer 1

C
since作介词或连词表示“自从……以来”常和完成时态连用。表示到现在为止完成的动作，且主语是谓语动词动作的承受者，谓语动词要用现在完成时的被动语态。