一. Affirmative （肯定形式）
I
am
happy.
You
We
They
are

He
She
It
is

I
am
happy.
You
We
They
are
He
She
It
is
缩写形式：
I am = I\'m
You are = You\'re
We are = We\'re
They are = They\'re
He is = He\'s
She is = She\'s
It is = It\'s
二. Negative （否定）
I
am not
interested.
You
We
They
are not

He
She
It
is not

I
am not
interested.
You
We
They
are not
He
She
It
is not
缩写形式：
I am not = I\'m not
You are not = You\'re not/ You aren\'t
We are not = We\'re not/ We aren\'t
They are not = They\'re not/ They aren\'t
He is not = He\'s not/ He isn\'t
She is not = She\'s not/ She isn\'t
It is not = It\'s not/ It isn\'t
三. 疑问句
Am
I
late?
Are
you
we
they

Is
he
she
it

Am
I
late?
Are
you
we
they
Is
he
she
it
肯定回答
Yes,
I
am
Yes,
you
we
they
are
Yes,
he
she
it
is
Yes,
I
am
Yes,
you
we
they
are
Yes,
he
she
it
is
否定回答
No,
I
I\'m not
No,
you
we
they
You\'re not/ You aren\'t
We\'re not/ We aren\'t
They\'re not/ They aren\'t
No,
he
she
it
He\'s not/ He isn\'t
She\'s not/ She isn\'t
It\'s not/ It isn\'t
No,
I
I\'m not
No,
you
we
they
You\'re not/ You aren\'t
We\'re not/ We aren\'t
They\'re not/ They aren\'t
No,
he
she
it
He\'s not/ He isn\'t
She\'s not/ She isn\'t
It\'s not/ It isn\'t
四. 用法
1. 系动词be
be为连系动词，中心词义是"是"，句型为"主＋系＋表"结构 。
如：
To help animals is helping people.(一般现在时)
The twins were very busy yesterday.(一般过去时)
It will be sunny tomorrow.(一般将来时)
She has been ill for over a week.(现在完成时)
2. 助动词be
助动词be，无词义，辅助主要动词一起在句中作谓语动词 。
1） be+doing：构成进行时态，有现在和过去两种进行时态 。如：
The girls is reading and copying the new words now.
Young Tom was always asking questions and trying out new ideas.
2）be+done：构成被动语态(主语是动作的承受者，done必须是及物动词) 。如：
Tea is grown in my hometown.(一般现在时的被动语态)
This building was built three years ago.(一般过去时的被动语态)
Our classroom has been cleaned and tidied already.(现在完成时的被动语态)
How could this kind of cakes be made in your home?(含情态动词的被动语态)
That is a day never to be forgotten.(动词不定式的被动语态)
3） be+going to do，表示"打算或将要做某事"，be有现在和过去两种形式 。如：We are going to plant trees in the park.I didn\'t know if she was going to come here.
4） be+to do，表示"按计划安排将要做某事" 。如：
The new shop is not to be opened till next Monday.
One night an angel came to Mary and told her that she was to have this special boy.
3. there be句式为
there be+主语部分＋状语部分，表示"某处存在某物"，be常用现在时，过去时和将来时等 。如：
Oh, cool! And there are many things to see.

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