主语从句的学案

　　自主探究

原句感知 自主探究 ①What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe.

②The earth became so violent that it was not clear whether the shape would last or not.

③What is even more important is that as the earth cooled down, water began to appear on its surface.

④It was not immediately obvious that water was to be fundamental to the development of life.

⑤What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas.

⑥So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved. (1)以上各句皆为主从复合句，句中黑体部分为名词性从句作主语，称之为主语从句。

(2)what引导主语从句，what在从句中作表语(句①)，主语(句③)，及宾语(句⑤)。

(3)whether引导主语从句，意为：是否(句②⑥)。

(4)可用it作形式主语，真正的主语为名词性从句(句④由that引导主语从句)。 　　

　　要点学习

语法点一 定义 　　在主从复合句中充当主语的从句即为主语从句。

　　What made her happy was that she won the game in such an important match.

　　令她高兴的是在这么重要的比赛中她获胜了。

　　It is decided that the meeting has been put off till next Monday.

　　已经定下来将会议推迟到下周一了。

语法点二 主语从句的连接词及其句法功能 　　1.连接词that和whether/if

　　(1)that在从句中不充当任何句子成分，本身无任何意义，只起连接作用，但不可省略。

　　That we are invited to the concert this evening is good news to us.

　　我们被邀请去参加今晚的音乐会，这对我们来说是个好消息。

　　(2)whether/if在从句中不充当任何句子成分，起连接作用，意为"是否"，不可省略。

Whether the plan will be carried out is still unknown.