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be动词的三种基本形式为:am,is,are。下面小编整理了一些be动词有哪些,和一些基本用法,供大家参考!
有am 、is 、was are、were、 being。
1、am,is和are用于不同的人称和数。am用于第一人称单数。例如:I am a teacher.我是一名老师。is用于第三人称单数,没有人和物的区别。
例如:—Who is he?—He is Tom’s father.—What’s this?—It is a book.are用于第二人称单、复数和第一、三人称的复数。例如:You are a student. We are students, too.
2、am,is和are可以帮助构成否定句和疑问句。在am,is或are之后加上not,即将句子变成了否定句;把be动词提到句首,即将句子变成了疑问句。
例如:I’m from China. →I’m not from China. →Are you from China? (对I am的提问比较特别)
He’s thirteen years old.→He isn’t thirteen years old.→Is he thirteen years old?
They are policemen. →They aren’t policemen. →Are they policemen?
看了以上例句,一定要注意am,is和are在句中的缩写形式。另外,am,is,are与this,these,those在一起时一般不缩写。
3、be也可以位于句首,表示向别人提出要求。例如: Be a good student! 做个好学生!
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 isa student.
They werein 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.
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 wasswimming 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 iswidely used around the world nowadays.
The window wasbroken by the naughty boy just now.
Your watch has already beenrepaired.
【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 isgoing to visit us next week. It isgoing 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 isabout 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 wasto have this special boy. The new store isto 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: Bepatient! (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。)
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