连接主语从句的从属连词主要有that, if, whether，和疑问词（what how where when ...)。that引导表示陈述句的主语从句，if和whether，whether...or not引导表示"是否"，引导一般疑问句。连接代词主要有who,whom,whose,what,whoever,whomever,whosever,whatever,whichever等。连接代词一般指疑问，但what, whatever除了指疑问外，也可以指陈述。连接副词主要有when, where, why, how, whenever, wherever, however等.

【举一反三】It suddenly occurred to him he had left his keys in the office.

A．whether B．where C．which D．that

【答案】D　　

【考点】考察名词性从句当中的主语从句。

【解析】it作形式主语，真正的主语为that he had left his keys in the office。且that在句中无意义，并不充当任何成分。

4. Pick yourself up. Courage is doing you're afraid to do.

A. that B. what C. how D. whether

【考点】考察名词性从句

【答案】B

【解析】本句是名词性从句中的宾语从句。What在句中充当引导词，同时也是动词do的宾语。句义：站起来！有了勇气，你才可以去做你不敢做的事情。ACD都不能在句中做宾语。故B正确。

【举一反三】He thought mattered most in improving your spoken English was enough confidence and practice.

A．Why B．What C．Which D．That

【答案】B

【解析】考查宾语从句的连接词。此处what作宾语从句的主语。句意：他认为提高英语口语的关键是有足够的信心和练习。

5. As John Lennon once said，life is_____ happens to you while you are busy making other plans.

　　A. which B. that C. what D. where

【考点】考察名词性从句