Question

since引导的时间状语从句。主句和从句的时态用什么？

Answer 1

since引导的时间状语从句表达自从......以来，主句通常我们现在完成时或者过去完成时，而从句则用一般过去时

Answer 2

Sb. has done sth. since sth. happened. 自从某事发生以来，某人做了某事
Sb. has been doing sth. since sth. happened.自从某事发生以来，某一直在做某事
这是 since的句型
since引导的时间状语从句中，要用过去时，表示“自从过去某个时间以来”
其主句用现在完成时或现在完成进行时（强调动作的持续性）。
He has learned five songs since he came here. 自从他来这儿以来，已经学了五首歌了。
She has been washing clothes since she got up. 自从她起床以来就一直在洗衣服。