五、非謂語動詞(Non-finite Verb)
　　在英語中，不是用于句子謂語而是用于擔任其他語法功能的動詞叫做非謂語動詞，也稱作動詞的非限定形式。
　　非謂語動詞有三種形式：不定式(the Infinitive)、分詞(the Participle)和動名詞(the Gerund)。
　　不定式
　　1. 構成與形式
　　不定式由不定式符號“to + 動詞原形”構成(有時不帶to)。前面可以加某些疑問代詞，如what, who, which, 或疑問副詞，如when, where, why等，構成特殊的不定式短語，如what to do next, how to get there等。
　　不定式形式有：

　　2. 用法
　　不定式不能單獨作謂語，沒有人稱和數的變化，具有名詞、形容詞和副詞的特征，而且還保留著動詞的特征，因而可以有狀語修飾，如果是及物動詞，還可以帶賓語，從而構成不定式短語。不定式或不定式短語在句子中可以作主語、表語、賓語、定語、狀語、主語補足語和賓語補足語。
　　1)作主語
　　To make a plan for our future is important.
　　How to get enough capital is still a question.
　　It is difficult to make a decision without knowing all the facts.
　　2)作表語
　　The important thing is to save lives.
　　What he wanted to do was to wash his hands of it.
　　3) 作賓語
　　I like to go for a walk in the warm sunshine.
　　We must remember to follow the safety rule.
　　4)作定語
　　She usually has a lot of meetings to attend in the evenings.
　　He was always the first to come and the last to leave.
　　There are some things to be grateful for.
　　5) 作狀語
　　She decided to work harder in order to catch up with the others.
　　He lifted a rock only to drop it on his own feet.
　　6) 作主語補足語
　　It is reported to be true.
　　The education of the young is seen to be of primary importance.
　　7) 作賓語補足語
　　Please remind me to take my medicine tomorrow.
　　They didn’t allow her to park the car in this street.
　　有一些動詞后用作賓語補足語的不定式通常不帶to。這種動詞有兩類：一類是感官動詞，如feel, see, hear, watch, notice等;另一類是使役動詞，如make, let, have等，如：
　　Did you notice him leave the house?
　　The made the boy go to bed early.
　　3. 時態與語態
　　1)完成式
　　I am sorry to have kept you waiting.
　　To have known her is an honor.
　　2) 進行式
　　They seem to be getting along quite well.
　　He pretended to be listening attentively.
　　3) 完成進行式
　　The famous singer is said to have been collecting folk songs in Xinjiang.
　　John is said to have been studying for a shole morning.
　　4) 被動式
　　I wish to be excused.
　　he was very pleased to have been given such an opportunity.