--Whendidyoubecomeavolunteerfortheelderly?--Twoyearsago...

问题详情：

--When did you become a volunteer fo r the elderly?

-- Two years ago. I        this group since then.

A. joined       B. took part in      C. have joined      D. have been in

【回答】

D

知识点：动词时态

题型：选择题