Not until ___to go on strike. A.all the demands has been turned down the workers decided B.had all the demands been turned down the workers decided C.all the demands had been turned down did the workers decide D.had all the demands been turned down did the workers decide 为什么?
标准答案C 因为not,until提前,所以,句子用倒装 原来的是: the workers didn't,decide to go on strike until all the demands had been turned down 这里until引导的是时间状语从句 前面是主句 现在的格式是 not+until引导的从句,+主句的一般疑问句(去除not) 你要记住这个公式