考点 16 动词不定式高考频度:★★★★★动词不定式定义动词不定式是非谓语动词的一种,由不定式符号 to+do 构成
没有人称和数的变化,在句子中不能作谓语,但可做主语、表语、宾语、状语和宾语补足语,具有名词、形容词和副词的特征
动词不定式仍保留动词的某些特点
形式时态积极被动一般式to doto be done完毕式to have doneto have been done进行式to be doing----完毕进行式to have been doing----否认式否认词(not/never)+动词不定式考向一 不定式的作用1
作主语:不定式作主语时,谓语用单数
往往用 it 作形式主语,把不定式放在谓语背面
It took us two hours to finish the job
(1)其他系动词如 look,appear 等也可用于此句型
(2)当不定式作主语的句子中又有一种不定式作表语时,不能用 It is
试比较:It is to negate my own idea to believe him
(错)To believe him is to negate my own idea
(对) (3)It is+ adj
of / for sb to do sth 构造中,当不定式的逻辑主语和前面的形容词可以构成系表构造时,用 of,否则用 for
作宾语(1)动词+不定式
☞He managed to escape from the fire
I find it hard to get along with him
☞(it 作形式宾语)(2)动词+疑问词+to,"特殊疑问句+不定式"相称于名词,作宾语
☞I don’t know what to do next/ how to do it next
不定式短语作宾语时,假如还