系动词,也称联系动词(Linking Verb),是用来辅助主语的动词。它本身有词义,但不能单独用作谓语,其后必须跟表语,构成系表结构说明主语的状况、性质、特征等情况。
在英语中,系动词的功能主要是把表语(名词、形容词、某些副词、非谓词、介词短语、从句)和它的主语联系在一起,说明主语的性质、特征、品性或状态。它有自己的但不完全的词义,不能在句中独立作谓语,必须和后面的表语一起构成句子的谓语。它虽是虚词,但是其用法是复杂的,而且不可忽视。
英语中的系动词后主要有以下几种(以动词be为例):
1.He is a student.(名词)
2.This bag is mine.(代词)
3.He is twelve this year.(数词)
4.The man is old.(形容词)
5.Look!Jim is over there .(副词或副词短语)
6.My father is at home today.(介词短语)
7.His wish is to be an artist.(不定式或不定式短语)
8.My favorite sport is swimming.(动名词或动名词短语)
9.The problem is when we will start tomorrow.(表语从句)
用法一:可以省略to be的系动词,比如:seem, appear, turn out
The examination turned out( to be)easy.
结果是考试很容易。
The baby appears(to be) hungry.宝宝似乎是饿了。
She doesn't want to go on studying. It seems a pity
她不想学下去了,这似乎很可惜。
用法二:作系动词的感官动词,比如:look,feel, sound, taste, smell
Tom felt sleepy so he decided to take a nap
汤姆感到困了,所以决定小睡一会儿。
You sound unhappy. what's the matter?
你说话听起来不高兴。怎么回事?