新编英语教程1unit7.ppt

Non-finite verb / non-predicate verb Infinitive (不定式): to do -ing, -ed participles Language Structure Do you know what to say to a person on his birthday in English? (The infinitive preceded by a wh-word used as the object, “疑问词不定式”作know的宾语。) Wh-疑问词后可接不定式构成不定式短语，在句中作主语、宾语、表 语等。如： ①When to leave for London has not been decided yet. （不定式在句子中做主语） ②Mr. Smith didnt know whether to leave or stay there. （不定式在句子中做宾语） ③The question was where to get the medicine needed. （不定式在句子中表语） 　　以上例句中疑问词＋不定式部分，均可转换为相应的从句形式。如： ①When to leave for London has not been decided yet. （不定式在句子中做主语） = When we should leave for London … ②Mr. Smith didn‘t know whether to leave or stay there. （不定式在句子中做宾语） = … whether he should leave or stay there ③The question was where to get the medicine needed. （不定式在句子中表语） = The question was where we could get the medicine (that was) needed. 常见的可以像know 这样带“疑问词不定式”作宾语（构成know wh- to do)的动词有：decide, find out, forget, inquire, learn, remember, see, settle, think, consider, understand, wonder等； 有些带双宾语的及物动词也可带“疑问词不定式”作宾语，如Can you advise me which to buy?用法如advice的动词有：tell, inform, show, ask等。 It takes us about forty-five minutes to go to the station. (The infinitive used as a postponed subject in the pattern it takes … to do something, 不定式做主语，但须后置，由it作为形式主语放在开头。) ①When to leave for London has not been decided yet. It has not been decided yet when to leave for London. It has not been decided yet when we should leave for London. We can see buses come and go in a busy street. (“come” and “go” are the bare infinitive used as the object complement, 不带to的不定式用作宾语补足语。) 用法与see相同的动词通常为感官动词，如：hear, feel, listen to, look at, watch, notice, observe, perceive, note等；或少数使役动词，如let, make, have, bid等。 要注意的是，这些动词用在被动语态中时，须补上被省略掉的不定式符号to。如： The buses could be seen to come and go in a busy street. 在感官动词后可用不带to的不定式补足语，也可用分词作宾语，其区别是，不定式宾补表示动作的完成；分词宾补表示动作正在进行，尚未完成；另外，动词的不定式表示动作的一次性，而分词作宾补表示动作的反复。如： I saw a soldier get on the train and disappeared. I saw a soldier getting on the trai