英语高手请进 where must the puma have come from?这是什么句型,为什么must后面不要

来源：学生作业帮编辑：作业帮分类：英语作业时间：2024/07/13 22:53:02

英语高手请进
where must the puma have come from?这是什么句型,为什么must后面不要加be的,为什么要加have?
which are found in american?为什么要加are
as the evidence began to accumulate ,began to accumulate是什么意思,为什么这么用?

这是新概念第……三册的第一课吧……
先说第二句.原句：Pumas are large, cat-like animals which are found in America.这里的which以及后面的部分是个定语从句,就是说有完整的句子结构,自然要有动词.这个从句修饰主语pumas,而从句中which指代的就是pumas,是复数,所以用的是are.
第三句,accumulate意思是“积累”,begin（began） to accumulate就是“开始积累”,放在原句里可以翻译成“随着证据的增多”.
第一句,must在虚拟语气中的用法,可以翻译成“到底”,陈述句形式是the puma must have come from ...,这个是最常出现的,must意为“一定,必定”.而关于have,have done sth是现在完成时,have作助动词形成语法结构表示时态；要注意的是done是动词的过去分词,come比较特殊,过去分词和原形同形.

英语高手请进 where must the puma have come from?这是什么句型,为什么must后面不要 where must the puma have come from? where must the puma have come from 其中must have done是什么用法? where must the puma have come from?请仿照这个句型造几个句子. where must the puma have come from,怎么翻译,有的说 must have done,可新概念第三册的第一课:"where must the puma have come from? they must have gone to the concert,后面是什么,mustn't they?这是英语的什 there must have句型? 改句型英语高手进You must walk to the zoo this afternoon.改___________ He must have come have yesterday ,didn'he?这里的have是什么意思?这句是什么 must＋have done 句型是Study must come first对?还是Study must come the first对?为什么?