表语从句

表语从句是指说明主语的身份，性质，品性，特征和状态位于系动词后。表语从句放在系动词之后的句子叫表语从句。

表语从句

• 定义
  • 表语
    • 表语是说明主语的身份、性质、品性、特征和状态。位于系动词后。
      • 主系表
        • I am fine. ( fine 是形容词，作表语) He is a boy. ( boy 是名词，作表语)
      • 系动词主要是be动词（am, is, are, was, were)，意为“是”。 其它系动词： 1）持续系动词（表示主语持续或保持一种状况或态度）：keep, remain, stay, stand 2) “像”系动词（表示看起来像）：seem, appear, look 3)感官系动词：look, feel, smell, sound, taste 4)变化系动词（主语变成什么样）：become, grow, turn, fall, get, go 5)终止系动词（主语已终止动作）：prove, turn out
  • 表语从句
    • 放在系动词之后的句子叫表语从句。
• 引导词
  • that引导表语从可时不充当成分，无含义，通常不省略
  • whether引导表语从句,表是否。(不能用”if")
  • 连接代词who/whom/whose/what/which...引导表语从句
  • 连接副词when/where/why/how..引导表语从句
  • 连接副词because why as if as though
• 特殊考点
  • 如果主语是表示“要求、建议、命令”的名词,如 suggestion,advice,order等,其后的表语从句常用虚拟语气,从句谓语用“(should+)动词原形”。My suggestion is that we should tell him.我的建议是我们应该告诉他。
  • as if/as though引导表语从句(常用虚拟语气) She looks as if she were hungry.她看起来好像饿了。It is not as though we were poor.又不是我们家里穷。
  • 区别：That is because... 表示“那是因为...That’s why...句型中 表示“那就是.....的原因”。 She is very familiar with the film.This is because she has already seen the film. That's why I want you to work there那就是我要你在那儿工作的原因。
  • The reason why...is that..表示“...的原因是... why引导的定语从句修饰先行词 reason，that引导表语从句。 The reason why he was late was that it was raining heavily.他迟到是因为天在下大雨。