英语常用连系动词
连系动词也称系动词（Link Verb），它本身具有实在意义，但不能单独作谓语，后边必须加上表语共同构成复合谓语。连系动词与其后面的表语合起来叫作系表结构。系表结构主要是为了说明主语的状况、性质、特征等情况。
一、表示状态的系动词
用来说明主语的状态，只有一个be，但be在不同的人称和时态中有不同的形式，有am、are、is、was 和were ，后接名词、形容词、分词、不定式、副词和介词短语等作表语。 例如:
The man is a science teacher.
Mary's new dress were colorful.
二、表示持续性的系动词
用来表示主语继续或保持一种状况或态度，主要有keep、remain、stay、lie、stand、contin
ue和rest等，例如:
Plea keep quiet.
Several problems remain to be solved.
I hope the weather will stay fine.
The whole city lay in ruins after the earthquake.
Mr. Black stands high in the public estimation.
The weather continues cold.
My grandfather will never rest idle.
三、表“像”系动词
用来表示“看起来像”这一概念，主要有em、appear和look，例如：
She ems very happy with the new job.
He appeared to be talking to himlf.
She looks happy.
四、感官系动词
感官系动词主要有feel、smell、sound、taste等，后面接形容词作表语，说明主语所处的状态，其意思分别为“摸/闻/听/尝起来……”。这几个动词的主语往往是物，而不是人。例如：
The tomatoes feel very soft.
The flowers smell very sweet.
The music sounds very pleasing to the ear.
The meat tastes delicious.
五、表示变化的系动词
这些系动词表示主语变化成什么样，主要有become、grow、turn、fall、get、go、come和run等，这些词后面大多数接形容词作表语，但become, turn, sound, remain, em亦可接名词作表语，只是turn 若跟名词则不加冠词。例如：
She became a famous writer.
His cold is growing wor.
In autumn the leaves turn yellow.
They first met at university and later fell in love.
It's getting cold.
The milk went sour.
My shoe came loo.
The river was beginning to run dry.
He turns doctor. = He becomes a doctor.
六、表终止的系动词
表示主语发出的动作已经终止，主要有prove和turn out，表达“证实”和“变成”之意。例如：
My advice proved( to be) wrong.
He proved a competent manager.
The party turned out (to be )very successful.
The rookie turned out (to be) the best hitter on the team.
七、学习系动词的注意事项
1.特别要注意“be+过去分词”所构成的系表结构与其所构成的被动语态的区别。系表结构侧重于表示主语的特征或所处的状态，通常没有由by引导的介词短语，如：The door was clod. 被动语态侧重于强调主语是谓语动词所示动作的承受者，表示动作；句中可以用由by引导的介词短语。如：The door was clod by me.
还要注意由“be+ V-ing”所构成的系表结构与其所构成的进行时态的区别。系表结构侧重于说明主语具有的特征或存在的状态，也可说明主语是什么。如：My job is teaching English. 进行时态侧重于强调主语正在做某事。如：Mr. Wang is reading an evening paper now.
2.要特别注意某些动词既可以做系动词，又可以做实意动词的用法。
有些系动词也是实意动词，该动词表达实义时，有具体词义，可单独作谓语，例如：
He fell ill yesterday.
He fell off the ladder.
The newly-invented soft drinking tastes quite unique.
The chef is tasting the fish carefully.
3.系动词除了接名词、形容词、分词、不定式、副词和介词短语等以外，还可接以下几种表语形式：
①能接as if/as though表语从句的系动词有：look（看起来），smell（闻起来），sound（听起来），feel（觉得）；appear（显得），em（似乎）等。例如：
He looked as if he had just stepped out of my book of fairy tales.
She emed as if (though) she couldn’t understand why Laura was there.
It sounds to me as though there’s a tap running somewhere.
She felt as if her head were splitting.
The river appeared as if enveloped in smog.
