Section_ⅢGrammar- 主语从句

　　语法图解

　　探究发现

　　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.

　　[我的发现]

　　(1)以上黑体部分在句中作主语。

　　(2)①句中的what在从句中作表语，但⑤句中的what在从句中作宾语；③句中的what在从句中作主语。

　　(3)②⑥句中的whether意为：是否。

　　(4)④句中It是形式主语，真正的主语是后面that引导的从句。

　　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 people excited was that the solar ship had completed around­the­world trip.

　　让人们激动的是太阳能船已完成了环游世界的旅行。

　　It worried the woman that her son was always playing computer games.

　　儿子一直在玩电脑游戏，这让这个女人很担心。

二、主语从句的连接词及其句法功能