Question

【题目】 It has been two and a half years _________ we left our primary school.

A. because B. than

C. unless D. Since

Answer 1

【答案】D

【解析】

试题分析：句意：自从我们小学毕业已经是两年半了。A. Because因为；B. Than比；C. Unless除非；如果不；D. Since自从。本题考查since引导的从句，主语用现在完成时。从句用一般过去时。根据题意故选D。