英语中am is are为什么叫Be动词?哪点和Be有关系? be又是什么词?

am is are 是be的表现形式，be是原型
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供参考

(1) be 其实代表了一组的动词
这组动词会因应
(1) 主语
(2) 时式
而变化

(2) 这组动词包括了
is, am , are
was , were
will be , shall be
have been , has been, had been
would be , should be
would have been, should have been
may be ( can, ought...)

(3) 例子
I 用 am / was / have been/ had been
We 用 are / were / have been/ had been
You (单数或众数)用 are/ were/ have been/ had been
其他单数主语 (he﹐ she, John, it...)
用is/ was/ has been

(4) 这是大概情况
可以先掌握这些
理解後熟练後
再接触其他细节