Section Ⅳ　Grammar & Writing

　　表语从句和主语从句

　　阅读下列句子并体会黑体部分的用法

　　1．But the big surprise of the evening was when I was elected prom queen!

　　2．My feeling is that they're going to be big one day.

　　3．It's a good thing that the exams are finished.

　　4．It's well­known that Americans are competitive.

　　一、表语从句

　　在复合句中，位于系动词之后作表语的从句称为表语从句。引导表语从句的引导词主要有以下几类：

类别 例词 说明 从属

连词 that，whether 两者在从句中都不作成分，that无实义；whether意为"是否"，不能替换 连接

代词 who，whose，what等 在从句中作主语、宾语、表语、定语等 连接

副词 when，where，why，how等 在从句中作时间、地点、原因、方式状语等 其他

连接词 because 主句主语不用reason as if/though 从句情况发生的可能性较小时，常用虚拟语气 　　　The most important thing is that we should find enough water for the oxen.

　　最为重要的是我们应该为牛找到足够的水。

　　The doubt is who has taken away the valuable vase.

　　疑点是谁拿走了那只贵重的花瓶。

My topic today is what most scientists are researching.