2019大学英语四级基础语法必备知识(4)
- 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。
2019大学英语四级基础语法必备知识(4)
Ⅱ 非谓语动词
不定式
形式
主动形式被动形式
一般式 to do to be done
完成式 to have done to have been done
实行式 to be doing
完成实行式 to have been doing
完成式:不定式的一般形式所表示的动作, 通常与主要谓语表示的动作(状态)同时(或几乎同时)发生, 或是在它之后发生. 假如不定式所表示的动作, 在谓语所表示的动作(状态)之前发生, 就要用不定式的完成式。
I am glad to have seen your mother (= I am glad I have seen your mother).
(比较: I am glad to see you.)
He is said to have written a new book about workers.
He pretended not to have seen me.
实行式:如果主要谓语表示的动作(状态)发生时, 不定式表示的动作正在实行, 这时要用不定式的实行式。
You are not supposed to be working. You haven't quite recovered yet.
We didn't expect you to be waiting for us here.
He pretended to be listening attentively.
完成实行式:在谓语所表示的时间之前一直实行的动作, 就要用不定式的完成实行式.
The struggle was known to have been going for twenty years.
We are happy to have been working with you.