连系动词本身有一定的词义,但不能独立作谓语,必须与表语一起构成谓语.
一、 连系动词的类型有：
1."存在"类:表示存在或具有某种特征或状态.这类连系动词强调"存在".常见的有:be(是),look(看起来),feel(摸上去),seem(似乎是),appear(似乎、显得),prove(证明是),smell(闻起来),taste(尝起来),sound(听起来)等.例如:
The story sounds true.
Those oranges taste good star.
2."持续"类:表示某种情况或状态的持续.这类连系动词强调"持续".常见的有:remain(依然),keep(保持),stay(保持),continue(继续、仍旧),stand(处于某状况或情形)等.例如:
Why don't you put the meat in the fridge?It will stay fresh for several days.
3."变化"类:表示由一种情况或状态变化成另一种情况或状态.这类连系动词强调"变化"后的情况或状态.常见的有:become(变成),turn(变成),grow(变得),get(变得)等.例如:
Put the fish in the fridge,or it will go bad in hot weather.
二、注意事项
1.有些连系动词通常不用于被动语态和进行时态中.如:feel,taste等词.例如:
-Yes,it feels very soft.
2.一般情况下,连系动词主要跟形容词或分词作表语.例如:
Be careful when you cross this very busy street.If not,you may get run over by a car.
3.能跟名词作表语的连系动词常见的有:be,become,appear,seem,prove,remain和turn等.注意:turn后跟(表示主语身份的)名词作表语时,不加冠词.例如:
Twenty years later,he turned teacher.
The population growth in China remains a problem.
4.连系动词也可跟不定式(to do / to be),常见的有:appear,seem,remain,prove,look等.例如:
Having a trip abroad is certainly good for the old couple,but it remains to be seen whether they will enjoy it.
On the long journey,Peter proved to be a most interesting guide.We all had a wonderful time.
表语是用来说明主语的身份、性质、品性、特征和状态的,表语常由名词、形容词、副词、介词短语、不定式、动词的-ing、从句来充当,它常位于连系动词（be,become,appear,seem等）之后.
例子:Africa is a big continent.
非洲是个大洲.
