2024届高三英语一轮复习主语从句讲义

主语从句 Subject Clauses 主语从句 Subject Clauses 如何得到带主语从句的复合句？ 陈述句： Money doesn’t grow on trees. This is obvious. 钱不会从树上长出来。这是显而易见的。 ↓在这个陈述句前加that,就可以变为名词从句。其作用相当于一个名词，可以作主语、宾语、表语、同位语从句等。 That money doesn’t grow on trees is obvious. 钱不会从树上长出来是显而易见的。 ↓句子“头重脚轻”，我们倾向于避免这种现象。可以用it作句子形式主语放在句子开头，把主语从句移到句子末尾。 It is obvious (that) money doesn’t grow on trees. 显而易见,钱不会从树上长出来。 这种从句并不是宾语从句，而是it的同位语，也就是真正的主语。如果主语从句在句首，that不能省略。但是，在it作句子形式主语，主语从句在许多形容词和少数几个名词之后可以省略that【详见附录】。但是主句若是疑问句，就不可以省略that。 一般疑问句： Does he have signed the contract? That doesn’t matter. 他签了合同吗？那不重要。 ↓在这个句话前加whether,并将其词序改为主语+谓语，就可以变为名词从句。 Whether he have signed the contract (or not) doesn’t matter. 他是否签署了合同并不重要。 ↓由whether引导的主语从句也可以用it作句子形式主语，把主语从句移到句子末尾。不过相较而言没有that那么常用。 It doesn’t matter whether he has signed the contract (or not). 他是否签署了合同并不重要。 相较于宾语从句，主语从句无论如何都不可以用if来引导。or not用不用都可以。 特殊疑问句：（带疑问词的疑问句，也就是以who(m), what, which, when, where, why和how等疑问词开头的疑问句。） When did he do it? That is a mystery. 他什么时候干的这件事？这是个谜。 ↓将其词序改为主语+谓语，就可以变为名词从句。 When he did it is a mystery. 他什么时候干的这件事是个谜。 ↓由疑问词引导的主语从句也可以用it作句子形式主语，把主语从句移到句子末尾。不过不常用。 It is a mystery when he did it. 练习： 一、将下列句子改为带主语从句的复合句。 1.Can we control pests without causing any ill effects? This still remains a question. . 2. Agriculture is the foundation of our country. This is well known. . 3. Some less-developed countries are suffering from food shortages. It is a serious problem. . 4. Some herdsmen in Inner Mongolia fix electronic sensors to their cattle to monitor their movements. That is true. . 5. Where he had lost his laptop. We wanted to know that. . 二、从（一）中的2、4句中选一句话，将其改为用it作