英语四级语法基础知识必备（04）

英语自学网

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        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
        进行式to be doing
        完成进行式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.
        进行式: 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进行, 这时要用不定式的进行式。
        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.
        完成进行式: 在谓语所表示的时间之前一直进行的动作, 就要用不定式的完成进行式.
        The struggle was known to have been going for twenty years.
        We are happy to have been working with you.