Question

Before a problem can be solved，it must be obvious____the problem itself is. A．what B．that

Before a problem can be solved，it must be obvious____the problem itself is. A．what B．that C．which D．why

Answer 1

A

A解析：考查名词性从句。句意为“在一个问题被解决之前，这个问题本身是什么必须要明确。”分析句子成分后可知，在before引导的时间状语从句中，it为形式主语，真正的主语为“the problem itself is”，在主语从句中is后缺少表语，故用what引导。