文档介绍：.页眉. 页脚.. 动词不定式的用法概念: 动词不定式由 to+ 动词原形构成。这里的 to 是不定式标志,没有词义。不定式具有名词、形容词或副词的某些语法功能, 又有动词的时态和语态的特点及作用。可以做主语、宾语、宾语补足语、表语、定语、状语。一、作主语动词不定式作主语时,句子的谓语动词常用单数,其位置有以下两种: (1) 把不定式置于句首。如: To get there by bike will take us half an hour. (2) 用 it作形式主语,把真正的主语不定式置于句后,常用于下列句式中。如: ① It+ be+名词+ to do It's our duty to take good care of the old. ② It takes sb+some time+to do How long did it take you to finish the work? ③ It+ be+ 形容词+b+ to do It is difficult for us to finish for swriting position ina quarter ofan hour. 在句型③中,常用表示客观情况的形容词,如: easy, difficult, hard, important, possible, impossible, comfortable, necessary, better; the first, the next, the last, the best, too much, too little, not enough ④ It+ be +形容词+ of sb+ to do It is stupid ofyou to write down everything the teacher says. 在句型④中,常用 careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise rude, clever, foolish, thoughtful, thoughtless ( 欠考虑的; 不考虑的), brave, considerate( 考虑周到的), selfish( 自私的)等表示赞扬或批评的词。在不定式前的 sb, 可看作其逻辑主语。这一句式有时相当于 Sb is +形容词+ to do句式,如: It's kind ofyou to help me with my English.=You are kind to help me with my English. ⑤ It seems(appears) +形容词+ to do It seemed impossible to save money. It seemed selfish of him not to give them anything. 他不给他们任何东西,这显得太自私了。注意:1)其他系动词如, look , appear 等也可用于此句型 2) 不定式作为句子主语时,动词用单数形式。 3) 当不定式作主语的句子中又有一个不定式作表语时,不能用 It is… to…的句型对应性: To see is to believe. 百闻不如一见。二、作宾语 1) 以下动词后,只能跟不定式作宾语 afford ( 付得起), agree (同意), aim( 力求做到), appear (显得), arrange (安排), ask (要求), attempt (试图), care (想要), choose (决定), claim (声称), condescend (屈尊), consent (准许), decide (决定), demand (要求), determine (决心), endeavor (. 页脚.. 力), expect (期待), fail (未履行), help (帮助), hesitate (犹豫), hope (希望), learn (学会), manage (设法), neglect (疏忽), offer ( 主动提出), plan (计划), prepare (准备), pretend (假装), proceed ( 接着做), promise (答应), prove (证明), refuse (拒绝), resolve (解决), seem ( 觉得好像), swear (发誓), tend ( 往往会), threaten (威胁), undertake (承诺), volunteer (自愿做),vow (发誓), want (想要), wish (希望) 举例: The driver failed t