They have been in the library since_______.

题目

They have been in the library since_______.
A:a long time ago
B:it had been open
C:eight o'clock
D:two hours
应该选哪个?为什么?

答案

很高兴为您选Csince的用法：译作“自从…以来”(1)接时间点：如 I have stayed in that country since 1995.要求：谓v.用现在完成时,而且须是延续性动词.(2)接一段时间 + ago：如 They have lived in that house sin...