that 引导名词性从句时,没有任何含义和语法作用,只是提示引导了名词从句;而what引导名词性从句时,在主从句中都要充当一定的句子成分,what的意思是“什么…”
例如:
1.The mountain is no longer ____ it used to be.
A. which B. that C. what D. as
答案C 。“山不是以前那个样子了”。以前“什么样”,对应了what。
2.There is much chance ____ Bill will recover from his injury in time for the race.
A. that B. which C. until D. if
答案A。that引导的名词从句陈述事实,说的即是前面的chance,为同位语从句。
三、定语从句与同位语从句中that的区别,主要看that在从句中有没有语法作用。
定语从句中的关系代词that在句中做宾语或主语,有时可以与 which 互换。同位语从句中的连词that只起连接作用,在从句中不担当任何句子成分;而如果句子是同位语从句,就应用连词that而不能用which。同位语从句一般放在表具体含义的名词如:fact、suggestion、truth、possibility、idea等后面,解释名词的含义或内容,而定语从句只是对先行词的限定和修饰。
例如:
The football star Henry expressed the hope that he would come to visit China again in 2008.
同位语从句,从句就是hope的内容;
The hope the football star Henry expressed is that he would come to visit China again in 2008.
定语从句,从句修饰hope,是“表达的”愿望。
再如:
1.…It's thirty years since we last met.
…But I still remember the story, believe it or not, ____ we got lost on a rainy night.
A. which B. that C. what D. when
答案为B。同位语从句,解释story。
2.I still remember the big names in the stories ______ my mother told me when I was young.