作句子主语的从句叫主语从句。主语从句通常由从属连词that，whether，if 和连接代词what，who，which，whatever，whoever 以及连接副词how，when，where，why 等词引导。that在句中无词义，只起连接作用；连接代词和连接副词在句中既保留自己的疑问含义、又起连接作用，在从句中充当从句的成分。
1.that 和whether做连接词引导的主语从句：
（1）That he finished writing the composition in such a short time surprised us all.
他在如此短的时间内写完禅指了作文，我们都很吃惊。
It is said that he has gone to shanghai.
据说他已经到
上海去了。
It seems that he has seen the film.
他似乎看过这部电影。
（2）Whether we will go for an outing tomorrow remains unknown.
我们明天是否去郊游仍然没确定。
It doesn't matter whether it rains.
下不下雨都没有关系。
Whether it is right remains a mystery.
它是否正确依然是个谜。
2. 连接代词引导的主语从句：
（1）What he wants to tell us is not clear.
他要跟我们说什么，还不清楚。
（2）Who will win the match is still unknown.
谁能赢得这场比赛还不得而知。历袭旁
（3）Whatever you did is right.
无论你做什么都是对的。
3.连接副词引导的主语从句：
（1）It is known to us how he became a writer.
我们都知道他是如何成为一名作家的。
（2）Where the English evening will be held has not yet been announced.
英语晚会将在哪里举行，还没有宣布。
（3）肢橡Why he was late for class is not clear.
他上课迟到的原因不清楚。
祝楼主进步，希望对你有所帮助。^_^o~ 努力！