请问这里为什么要用动词不定式?he was afraid to leave his home.改成 he was afraid left his home.

请问这里为什么要用动词不定式?he was afraid to leave his home.改成 he was afraid left his home. i'm going to paint it pink.请问为什么这里要用动词不定式这里的动词不定式做什么语?to在这里是介词还是动词不定式符号?为什么to后不加动名词? 这里为什么要用动词不定式?After reading the letter,he went on (to write)a reply.为什么不用writing? 请问这里为什么要用动词不定式来做定语.Edison was the first man to invent the electric lights.这里为什么 要用动词不定式to invent做定语来修饰前面的man而不是用ing形式呢,比如下面这样：Edison was the fir No one is allowed,no matter who he is,___until the construction is completed.A.to enter B.entering C.entered D.enter这里为什么用动词不定式. 为什么要用动词不定式英语中使用动词不定式的意义是什么 there is said to be oil under the North Sea.这里的to be是什么语法结构?如果是动词不定式,那为什么要用动词不定式?还有个句子：he is said to be a genius.他被称作天才.同样的问题. He is the last one to go to bed every day?这一句话为什么要用动词不定式? He has a lot of homework to do.这里为什么不用不定式的被动语态?homework不是被作吗?那么不定式的被动语态又该用在什么场合?当不定式修饰want ,have 等动词的宾语，而句子的主语是不定式的逻辑主 英语不定式动词为什么要加介词 He is careful enough to look after his brother?是careful enough还是carefully enough?为什么?动词不定式在这里作什么成份? He was nowhere to be seen.为什么要用不定式 什么是动词不定式,什么时候用动词不定式,? he feels differently.这里副词为什么修饰系动词系动词不是用形容词修饰吗？ circle and write这句话是什么意思?He goes to school by subway.这里面HE后面为什么用的是 goes?she rides her bike to school这里的rides是复数形式吗?为什么要变成复数形式?they walk to school为什么这里面没有把wa 为什么这里要用不定式,这里的不定式做定语,I've got something to eat.（我有东西吃）都说不定式做主语,宾语等,为什么要要用不定式呢? 1,He was to cross the road when a car suddenly raced to him.（在was 后面加about,.我们知道was+动词不定式也可以表示将来为什么这里要用was about to 表将来呢?）2,She said she was going to come when her mother told her supp 什么时候用动词不定式~