河北 侯世敏
主语从句、表语从句和宾语从句在句子中的功用相当于名词，因此这三种从句又统称为名词性从句。名词性从句是学生在中学阶段所学的一个重要语法项目，内容繁杂，不易掌握，许多学生在使用时容易犯这样或那样的错误。现就学生常犯的一些错误分析如下：
1。 误：The question is if they can work out the difficult math problem 。
正：The question is whether they can work out the difficult math problem 。
析：引导主语从句、表语从句时，常用whether不用if。又如：
Whether Tom goes with us makes no difference 。
What the doctor really doubts is whether my mother will recover from the serious illness 。
2。 误：That he said surprised all of us 。
正：What he said surprised all of us 。
析：what引导主语从句并在主语从句中作said的宾语。当that引导主语从句时，不作句子成份，只起连接作用。
3。 误：I believe no matter what he says 。
正：I believe whatever he says 。
析：whatever在这里引导宾语从句，no matter what只能引导状语从句。
4。 误：He asked how much should he pay the doctor 。
正：He asked how much he should pay the doctor 。
析：一般来说，宾语从句的语序是陈述句语序。
5。 误：Who leaves the room last should lock the door 。
正：Whoever leaves the room last should lock the door 。
析：who可以引导主语从句，但往往具有疑问的意义；而whoever则没有疑问的意义，相当于anyone who 。
6。 误：He wants to become a friend of whomever shares the same interest 。
正：He wants to become a friend of whoever shares the same interest 。
析：whoever引导宾语从句并在从句中作主语，故不能用whomever 。
7。 误：It all depends on if they will support us 。
正：It all depends on whether they will support us 。
析：they will support us 在句中作depends on的宾语，故用whether，而不用if引导。
8。 误：The reason why he didn”t come is because his mother was ill 。
正：The reason why he didn”t come is that his mother was ill 。
析：The reason why … is …句型中，应用that 引导表语从句，表示“……的原因是……”。
9。 误：We didn”t know if or not she was ready to start work 。
正：We didn”t know whether or not she was ready to start work 。
析：whether引导宾语从句时可以和or not 连用，而if则不能。
10。 误：He is famous as an English teacher is well known 。
正：That he is famous as an English teacher is well known 。
析：that引导主语从句时不能省略。
11。 误：That really interested the children was how to use the computer 。
正：What really interested the children was how to use the computer 。
析：what引导主语从句在从句中作主语，而that引导主语从句时，不作句子成分，也没有任何含义。
12。 误：The man asked his son where he found his glasses 。
正：The man asked his son where he had found his glasses 。
析：宾语从句中动词find的动作是在主句动词ask之前发生的，因此要用过去完成时来表达。
13。 误：All what they need is enough time to prepare for the examination 。
正：All that they need is enough time to prepare for the examination 。
正：What they need is enough time to prepare for the examination 。
