名词从句

概念：三种句子充当另外一句子的四种句子成分
调整：
1. 陈述句：句前 + that (当宾语时可省略)
e.g. a. That the moon itself does not give off lights is common knowledge.
b. I’ve learned (that) love, not time heals all wounds.
2. 一般疑问：变陈述句语序，句前 + whether(当宾语时可用if)
e.g. a. My question is whether people will live on the moon someday.
b. I don’t know if/whether he needs my help.
3. 特殊疑问：变陈述句语序
e.g. a. Money is what we are badly in need of.

句子类型	引导词	从句中作用
陈述句	that	不做成分
一般疑问	whether, if	不做成分
特殊疑问	连接副词when, where, why, how 连接代词who, whom, what; which, whose	连接副词做状语 who, whom, what做主语/表语/宾语 which, whose做定语,后+名词连用

it形式主语：it在句首，主句在后面
e.g. a. It is common knowledge that the moon itself does not give off light.
b. It is not known where they came from.
it形式宾语：复合宾语中：动词 + it + 宾补 + 宾语从句
e.g. I find it encouraging how many young women are pursuing careers in
science.
双宾语：e.g. Could you tell me where the post office is?
介词后做宾语：e.g. You should vote for which candidate you assume best.
形容词后做宾语：e.g. I am afraid that I can’t come.
并列宾语从句中that不省略：e.g. I once read that “*” and that “*”.
reason后的表语从句：引导词用that，不用because.
e.g. The reason (why) he was dismissed is that he was careless and irresponsible.

**嵌套：**a. I realized that what I said was not exactly what I meant to say.
b. The question is how what you have learned can be put into practice.