英语中be动词的用法大全
一、系动词be
作为系动词（也叫连系动词，link verb）的be，是英语学习者接触最早的用法，而且其用法也很多。其基本含义为“是”，基本用法结构为“主语+be+表语”，也就是我们常说的主系表结构，其中的表语一般都由名词、形容词、数词或表地点、时间等的短语来充当。
系动词be有各种时态的变化，也会和情态动词连用。
（一）be的时态变化
系动词be会有一般现在时、一般过去时、一般将来时、现在完成时、过去完成时等的时态变化。如：
He is a student.
They were in the park yesterday.
It will be cloudy tomorrow.
He has been ill for six days.
It had been three hours before she left the hat shop.
（二）be与情态动词的连用
其用法为：情态动词+系动词be原形。如：
It must be Lucy's book. Her name is on the cover.
It can be very difficult for us to memorize too many words within such a short time.
She should be here on time tomorrow.
更多有关系动词的用法，大家可以戳这里：一站式珍藏：英语九大词类
二、助动词be
作为助动词，be没有具体含义，而是与主要动词一起构成句子的谓语动词。这种情况下，be主要用来构成进行时和被动语态。
（一）进行时态中的be
此时，be可以与主要动词的现在分词一起，构成各种进行时态。如：
He is reading in the library now. （现在进行时）
She was swimming in the river this time yesterday. （过去进行时）
They will be arriving in Beijing tomorrow. （将来进行时）
We have been learning English for ten years. （现在完成进行时）
（二）被动语态中的be
助动词be能够与主要动词的过去分词一起构成被动语态，即be done结构。如：
Chinese is widely used around the world nowadays.
The window was broken by the naughty boy just now.
Your watch has already been repaired.
【注意】
助动词be能够构成特殊句型。如：
1、be going to do
be going to do表示“打算或将要”。如：
He is going to visit us next week.
It is going to rain soon.
2、be about to do
be about to do表示“刚要，即将”。与be going to do表“将要”不同的是，be about to do表示的是说完话后马上就要去做或是短期内马上就要去做。如：
The plane is about to take off in five minutes' time.
3、be to do
be to do表示“按计划要做”。如：
One night an angel came to Mary and told her that she was to have this special boy.
The new store is to be opened tomorrow.
三、特殊句型中的be
（一）There be句型
与上面用法都不同的是，be可以与there一起构成there be句型，用来表示存在。考虑到There be句型较为重要，内容较多，在此不做赘述，后面再找时间跟大家单独分享。今天就先给几个常见的例句。
There is a white ruler on the desk.
There were a great many people in the car race last year.
（二）祈使句中的be
这种情况下，句子一般以Be开头或是Don't be开头，表示命令或建议等。如：
Be patient! （耐心点！）
Don't be so hard on me! （不要对我们这么严厉！）
（三）虚拟语气中的be
be有时可以放在句首，引起虚拟语气。如：
Be he rich or poor, she will marry him.
Be it true or not, she will see it herself.
此时的be引导的句子其实相当于一个让步状语从句。以上两句话就相当于：
Whether he be rich or poor, she will marry him. （无论他是否有钱，她都会嫁给她。）
Whether it be true or not, she will see it herself. （无论这是否是真的，她都会亲自去见证。）