Question

he and she___each other since they were children,so nobody was surprised to hear they were married

A knew B have known C had known D were known
详细说明

Answer 1

您好，
答案为C
释义：他们从小青梅足马，听说他们喜结连理，人们一点都不惊讶。
since（自从。。。）用可用于现在/过去完成时态中，
从最后一个分句我们可以判断整句话的时态是过去时态，
所以since在这里用于过去完成时态
since引导的时间状语从句的时态是一般过去时，
主句的时态则是现在/过去完成时态
当然since还能引导原因状语从句，这时解释为：由于
since he was a little boy，he could not move the heavy stone
由于是个小孩，他搬不动那块大石头。
希望能帮到您

Answer 2

选C
因为since前面加完成时态，后面是一般过去时，但是因为后来是was ，所以前面的现在完成时还要退一格时态，选C

Answer 3

我觉得是B吧！！！

Answer 4

C

Answer 5

C