I __ he had finished his homework at this timeA.think B.thought这里为什么不用think呢?

问题描述:

I __ he had finished his homework at this time
A.think B.thought
这里为什么不用think呢?

你好。如果一定要用think,就必须这样改写句子:
I THINK he had finished his homework BY this time YESTERDAY.
语法:by + 过去时间------过去完成时。

从句用过去完成时,即过去的过去,主句应该提供一个过去的背景,故用一般过去时

I __ he had finished his homework at this time
选B
因为从句部分原本的时态是一般过去时,因为有时间状语【at this time】
因为现在用的是过去完成时,所以只可能是主句时态是一般过去时,导致从句时态往前推了一格