Our teachers always give us good advice.We should follow___.A.What they say B.waht they said 为A?

题目

Our teachers always give us good advice.We should follow___.A.What they say B.waht they said 为A?
为什么选A 如果选B 原句要怎么改?

答案

Our teachers always give us good advice 是一般现在时,所以follow后面应该跟着主句的时态一样.
Our teachers gave us good advice,we should follow waht they said.
(should作独立的情态动词时候没有过去式和过去分词