主语从句
主语从句是在句子中充当主语的从句。 它与其它名词性从句一样，通常由连接代词或连接副词引导。
1. 由that 引导的主语从句
* That she lacks experience is obvious. 她缺少经验，这是显然的。
* That you will win the medal seems unlikely. 你想获得奖牌看起来是不可能的。
* That you are so indifferent bothers me. 你如此冷淡使我很烦恼。
2. 由连接代词引导的主语从句
* What you need is more practice. 你需要的是更多的练习。
* Which of them escaped from the prison is still a mystery. 他们哪一个是从监狱里逃跑的，仍然是个谜。
3. 由连接副词引导的主语从句
* When they will come hasn't been made public. 他们什么时候来还没有公布。
* Where she has gone is not known yet. 她去了哪儿，还不知道。
* How the prisoner escaped is a mystery. 犯人是如何逃跑的是个迷。
* Why he did it will remain a puzzle for ever. 为什么他做那件事将永远是个谜团。
4. 由whether引导的主语从句
* Whether he will join us won't make too much difference. 他是否加入我们，没有太大的差别。
* Whether she is coming or not doesn't matter too much. 她来不来都无关紧要。
5. 由 what 引导的主语从句
* What she did is not yet known. 她干了什么尚不清楚。
* What I want to know is this. 我想知道的就是这事。
* What you need is more practice. 你所需要的是更多的训练。
6. 以it作形式主语的主语从句
1） it + be + 形容词 + 从句
* It is doubtful whether she will be able to come. 她是否能来令人怀疑。
* It is essential that he should be here by the weekend. 周末之前，他应该到这里是必要的。
* It was clear (that) his words pleased her. 显然他的话使她很高兴。
2） it + be + 名词 + 从句
* It is common knowledge that the whale is not a fish. 鲸鱼不是鱼，这是常识。
* It is no surprise that Bob should have won the game. 鲍勃会赢得这场比赛，这不足为奇。
3） it + 动词 (+宾语或状语) + 从句
* It does not interest me whether you go or not. 我对你去不去不感兴趣。
* It shocked me that Peter did not tell anybody where he was. 让我吃惊的是彼得没有告诉任何人他在哪里。
* It happened that she was out. 碰巧她外出了。
4） it + 动词的被动语态 + 从句
* It is thought that he is the best player. 大家都认为他是最好的选手。
* It is estimated that the vase is 2000 years old. 据估计这个花瓶有2000年的历史。7. 由whatever, whoever, whichever 等引导的主语从句
* Whatever was said has left us much to think. 这里说的话都应当保密。
* Whoever says that is a liar. 说那话的人是个骗子.
* Whichever comes in first will receive a prize. 谁先到就会获奖。
8. 由 just because 引导的主语从句
由just because 引导的主语从句通常只用于 "Just because...doesn't mean..."句型中。
* Just because her eyes don't tear, doesn't mean her heart doesn't cry. 只是因为眼泪没有掉下来，并不代表她在心里没有哭泣。
* Just because he's over sixty doesn't mean he must retire. 仅仅是年过60这一点并不意味着他一定退休。
