be是一個(gè)多功能動(dòng)詞，在初級英語里可見四種用法：

功能一，系動(dòng)詞be

be為連系動(dòng)詞，中心詞義是"是"，句型為"主+系+表"結(jié)構(gòu)。be的形式常用am, is, are(現(xiàn)在式);was, were(過去式);will/can/may/must be(助動(dòng)詞/情態(tài)動(dòng)詞+原形);have/has/had been(助動(dòng)詞+過去分詞)等。如：

To help animals is helping people.(一般現(xiàn)在時(shí))

The twins were very busy yesterday.(一般過去時(shí))

It will be sunny tomorrow.(一般將來時(shí))

She has been ill for over a week.(現(xiàn)在完成時(shí))

功能二，助動(dòng)詞be

助動(dòng)詞be，無詞義，輔助主要?jiǎng)釉~一起在句中作謂語動(dòng)詞。用法如下：

1. be+doing：構(gòu)成進(jìn)行時(shí)態(tài)，有現(xiàn)在和過去兩種進(jìn)行時(shí)態(tài)。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：構(gòu)成被動(dòng)語態(tài)(主語是動(dòng)作的承受者，done必須是及物動(dòng)詞)。如：

Tea is grown in my hometown.(一般現(xiàn)在時(shí)的被動(dòng)語態(tài))

This building was built three years ago.(一般過去時(shí)的被動(dòng)語態(tài))

Our classroom has been cleaned and tidied already.(現(xiàn)在完成時(shí)的被動(dòng)語態(tài))

How could this kind of cakes be made in your home?(含情態(tài)動(dòng)詞的被動(dòng)語態(tài))

That is a day never to be forgotten.(動(dòng)詞不定式的被動(dòng)語態(tài))

3. be+going to do，表示"打算或?qū)⒁瞿呈?，be有現(xiàn)在和過去兩種形式。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"按計(jì)劃安排將要做某事"。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.

功能三，there be

there be句式為：there be+主語部分+狀語部分，表示"某處存在某物"，be常用現(xiàn)在時(shí)，過去時(shí)和將來時(shí)等。如：

Oh, cool! And there are many things to see. There is even a deer park in Sanya.

There are about 80 pyramids in Egypt.

Will there be a football match in your school next week?

功能四，實(shí)義be

可以將be視為實(shí)義動(dòng)詞，因?yàn)樗哂袑?shí)際的詞義，如"成為;做;發(fā)生;舉行;逗留;到達(dá)"等。如：

His daughter wants to be a doctor for animals in her twenties.

Kate’s birthday party will be at half past six this evening.

Jim has been in China for more than two years, but he has not yet been to Yichang.