主语从句：从句在复合句中充当主语
1， that 开头的句子
That he can speak English is known to all 众所周知，他能说英语的
2， It 做形式主语的从句
It is interesting that he can speak English and French 他能说英语和法语是很有趣的
It is a surprise that he can speak English and French 他能说英语和法语是一个惊喜。
It is reported that he can speak English and French 据报道，他能说英语和法语。
It 动词（appear显得，happen to sb碰巧，matter重要，occur出现，turn out结果是）
It turns out that he can speak English and French 结果是他能说英语和法语。
3， whether 引导的从句
Whether you can speak English depends on your effort
是否你能说英语是取决于你的努力
Whether you can speak English is doubtful =It is doubtful whether you can speak English
你是否能说英语是没准的
4， 其他连接词的主语从句
1， What you want can change your life 你所想要的能改变你的生活
2， Who you can see can make you better 你能看到的人能让你更好。
3， Whoever you meet can make you better 无论你见到谁，都能使你更好。
