It____five years since they ____ to China.
问题描述：
It____five years since they ____ to China.
A.was,moved B.was ,have moved C.is,have moved D.is,moved
答
1.It is some time(一段时间) + since引导的时间状语从句
= It has been some time(一段时间) + since引导的时间状语从句
该固定句型意思是“自从...以来已经多久时间了”.
2.其中要求since引导的从句必须采用一般过去时,而主句是一般现在时或现在完成时.
综上,选D