两道关于状语从句的题

题目

两道关于状语从句的题
1 I have heard these sons and daughters say they never fully appreciated their mothers_____it was too late to tell them.
A as B that C until D when
2 Stop making so much noise_____my neighbor will start complaining.
A or else B but still C unless D if
请问选什么?
请说明理由。

答案

1、选C,句意我听说这些人从没有全心全意的感激他们的母亲直到已经太迟了,意思就是这些人在母亲活着的时候没有告诉母亲他们有多么的感激母亲,当想告诉母亲的时候母亲已经不在了.
其它选项都不对.AD都是当……时候,as也有尽管的意思,但是不对
2、选A,否则得意思,句意：快停止制造噪音否则邻居又要抱怨了
B但是仍然,逻辑不对,C除非,如果不,逻辑不对,语法也不对,unless后一般现在表将来.D语法不对