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areas the evidence began to accumulate ,began to accumulate是什么意思,为

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areas the evidence began to accumulate ,began to accumulate是什么意思,为
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?

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areas the evidence began to accumulate ,began to accumulate是什么意思,为
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.

1.这里的must是表推测，你可以把它变成陈述句，就好理解了，The puma must have come from America. must have done sth 是对已经发生的事情作出的推测。He must have known it before I told him. 在我告诉他以前他准是已经知道了。
2. which 应该是指代的上文某个复数的东西，你再看看上下文。

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1.这里的must是表推测，你可以把它变成陈述句，就好理解了，The puma must have come from America. must have done sth 是对已经发生的事情作出的推测。He must have known it before I told him. 在我告诉他以前他准是已经知道了。
2. which 应该是指代的上文某个复数的东西，你再看看上下文。
3. began to accumulate是越来越多的意思，你可以把这看做一个词组。accumulate累积。
enjoy studying english

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情态动词+动词完成时,即情态动词+have+done.表示对过去的行为或动作进行推测,评论或者判断.
1.must have done.
表示对过去某事的肯定猜测，其否定或疑问形式都用can/could来表示。
例如：since the road is wet,it must have rained last night.
2；当然对现在发生或者将来发生的事...

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情态动词+动词完成时,即情态动词+have+done.表示对过去的行为或动作进行推测,评论或者判断.
1.must have done.
表示对过去某事的肯定猜测，其否定或疑问形式都用can/could来表示。
例如：since the road is wet,it must have rained last night.
2；当然对现在发生或者将来发生的事情，要用must do表示猜测，否定为can’t do
he must understand that we mean business.
you must be hungry after a long walk.
反意疑问句中含有Must的情况主要有以下几种：
1）作为情态动词表“必须”，这时反意疑问句直接用mustn'/needn't
2)当must表示推测时又分以下几种情况：
a：对现在事实的推测，反意疑问句与must后面的动词呼应，如:
You must be joking,aren't you ?
b:对过去事实的推测，表示动作的时候用did 当助动词，表示状态时用was，如：
Mr Green must have been punished for his being rude at the meeting，didn‘t he ?(格林先生一定因为昨天在会上鲁莽的行为被处罚了，是吗？） 被处罚表示一个动作
She must have been a policeman ,wasn't she ?（她过去一定是个警察，是吗？） 是警察表示一种状态
对现在情况的推测，问句部分用主动词（do,be)一般现在时的适当形式。若是现在进行时，问句部分用现在进行时的适当形式表示。若是there be结构，问句用isn't/aren't there。如：
1)He must be there,isn't he?
2)He must have a big family,doesn't he?
3)He must be waiting outside,isn't he?
4)There must be some students in the room,aren't there?
对已发生的过去情况的推测，若陈述句谓语部分有“must have done”，而且有表示过去的时间状语，问句部分用didn't；若没有表示过去的时间状语，问句部分用haven't或hasn't。如：
1)They must have gone there last night,didn't they?
2)They must have arrived by now,haven't they?（根据by now来判断）
3)They must have been to the Great Wall,haven't they?
若是被动，应按被动结构来处理。如：
1)The room must have been cleaned yesterday,wasn't it?
2)The room must have been cleaned,hasn't it?
若句中有表示过去完成时的时间状语，问句部分应用hadn't.如:
They must have learnt 5000 English words by the end of last term,hadn't they?
(本题中must表推测，如果将它去掉，还原为真实句就是They had learnt 5000 English words by the end of last term.因此，反意问句是hadn't）
二、as the evidence began to accumulate 随着证据越来越多
accumulate表一段时间连续不断地收集的结果。
一）是收集的累积动作没有结束，
二）是个人认为AS the evidence began to accumulate和后面专家的调查相连，是因果关系吧！

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