动词不定式练习题及讲解.doc

动词不定式用法要点讲解 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： It＋be＋名词＋to do Its our duty to take good care of the old. It takes sb+some time+to do How long did it take you to finish the work? ③It＋be＋形容词＋for sb＋to do It is difficult for us to finish writing the composition a quarter of an hour. It＋be＋形容词＋of sb＋to do It is stupid of you to write down everything the teacher says. It seems(appears)＋形容词＋to do It seemed impossible to save money. 二、作宾语 不定式作宾语 以下动词后，只能跟不定式作宾语。如：agree,ask,aim,arrange,choose,decide,demand,expect,fail ,help,hope,lean,longmanage,offer,plan,prepare,pretend,promise,refuse,wish等，这些词大部分可接th at引导的从句。如： When our visit to the farm was over, we expected to starback on foot. When our visit to the farm was over, we expected that we would start back on foot. ②当复合宾语中的宾语是不定式时，先用形式宾语it代替不定式，把不定式置于补语之后，即：主语＋动 词＋it＋补语＋to do句式 He feels it his duty to help the poor. ③介词but,except,besides+to do(do) 在这种句型中，如介词前有动词do，后面应接不带to的不定式；如无do，则接to不定式，即带do不带to， 带to不带do。如： The enemy soldiers had no choice but to give in. 部分动词后面，既可接动词不定式，也可接动名词作宾语，意义不变。如：begin,continue,start,hate,like,love,need,require,want等。 在need,require,want后接-ing形式，表示被动意义，也可接不定式，但要用被动形式，如：Your handwrting needs improving(tobe improved). hate,love,like接不定式表示特定的未来事件，接动名词表示目前 正在进行的活动或一般的行为。 在下列情况下，一般要用不定式： hate,like,love前有would(should)时，如：Id like to have a cup of coffee. 当谓语动词begin,continue,start等是进行式时，如：Thestudents are starting to work on the difficult maths problem. begin,continue,start与know,understand等状态动词连用时，如：I soon began to understand what was happening. advise,allow,encourage,forbid,permit等动词后接动名词作宾语，或带不定式作宾语补足语。如： Our teachers dont permit our swimming in the lake. Our teachers dont permit us to swim in the lake. 4．部分动词后接不定式或动名词时，意义差别较大，应根据句子语境选择使用。 forget,remember,regret后接不定式，表示现在或未来的动作，接动名词表示动作已经发生。如： We regret to tell you that all of you are not invited to attend the meeting. T