内容正文:
Unit 5 First aid
5.2 Learning About Language
复习动词ing形式
一、动词ing形式的基本情况
1.动词ing形式是动词的一种非谓语形式,包括现在分词和动名词两种。
动词ing形式在句中的语法作用:动名词在句中作主语、宾语、表语和定语,现在分词在句中作状语、宾语补足语和定语。
2.动词ing形式的时态和语态:
语态
时态
主动语态
被动语态
一般式
doing
being done
完成式
having done
having been done
Reading aloud is a good way to learn a language.
大声朗读是学习语言的一种好方法。
Having studied his lessons very hard,he passed the exam.
努力学习了功课, 他通过了考试。
The building being built now will be finished next month.
正在建设的建筑物下个月将完工。
二、动词ing形式作主语
1.动词ing形式作主语时,往往表示经常性、习惯性的动作,通常置于句首。
Saying is one thing,and doing is another.
说是一回事,而做是另一回事。
Having a walk every day helps to make one keep healthy.
每天散步有助于一个人保持健康。
[名师点津]
动名词作主语时,谓语动词用单数。
Climbing mountains is really difficult for the old.
对于老人来说爬山确实困难。
2.形式主语it代替动词ing形式作主语。
此类句式常见的有:
It's a waste of time doing sth.做某事是浪费时间
It's useless/worthwhile doing sth.做某事没用/是值得的
It's no good/use/fun doing sth.做某事没好处/没用/没意思
It is a waste of time persuading such a person to join us.
劝说这种人加入我们是浪费时间。
It is