动词不定式to have seen怎么替换?是将have换成be还是being,或者干脆换成that they have seen?整句是这样,They claim to have seen monsters in the sea.我需要解释怎么换,为什么.

动词不定式to have seen怎么替换?是将have换成be还是being,或者干脆换成that they have seen?整句是这样,They claim to have seen monsters in the sea.我需要解释怎么换,为什么. 动词之后接一系列动词不定式,除第一个不定式用to外,后面的不定式通常都不用to.那么这个应该怎么理解It is nice to have fridends to talk and to do things with. Dinosaurs have completely died out on the earth,never____again.A.to be seen B.being seen为什么选A不选B?结果状语中 不定式不是表出乎预料的结果吗?怎么用的是不定式呢? 动词不定式的完成式 to have done 表示什么? 当句子是动词不定式完成时时,谓语动词是不带to的动词,后怎么接?我是想问，动词不定式完成时就是....to have +p.p的形式，如果谓语动词是let make 一类不带to的动词后跟动词不定式完成时是不 当句子是动词不定式完成时时,谓语动词是不带to的动词,后怎么接?我是想问,动词不定式完成时就是.to have +p.p的形式,如果谓语动词是let make 一类不带to的动词后跟动词不定式完成时是不是也像 动词不定式怎么用, they have much homework to do.中为什么是to do?而不是do?什么是动词不定式?什么时候用动词不定式? have you ever seen yao ming( ) basketball?A to play Bplay Chave played Dplayed请问这里为什么选B哪?是因为play 在主动句中是省略TO的动词不定式吗?老师给我们讲的是play 在主动句中省略TO的动词不定式 ·· I believe the child to have told the truth 怎么理解I believe the child to have told the truth 为什么用动词不定式 怎么区分哪些句子是不带to的动词不定式? 动词不定式包括to 例如：The only person I have ever known to have a skeleton in the cupboard..这句话know后的to是独自做宾语+动词不定式.还是动词不定式是to have a skeleyon. 动词不定式包括to 例如：The only person I have ever known to have a skeleton in the cupboard..这句话know后的to是独自做宾语+动词不定式?还是动词不定式是to have a skeleyon? 省to的动词不定式变被动该怎么变?据说是要还原to,但是刚刚看到一个句子,he was last seen leaving his office at 7 p.m.yesterday,这一句为什么不用还原?he was last seen to leave和he was last seen leaving有什么区别 动词不定式不加to to be about+动词不定式 I DON'T HAVE MUCH TO DO.这个TO在这里是什么意思?是动词不定式吗? 动词不定式作定语 怎么理解啊when is a good time (to fish) 是不是动词不定式