系动词be有各种时态的变化，也会和情态动词连用。下面小编告诉你小学四年级英语be动词用法，大家一起来看看吧!
小学四年级英语be动词用法:
(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.
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(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.
there be与have的比较:
■不同之处
一、用法不同
there be 表示某个时间或地方“存在”某人或某物，而have表示主语“拥有”某人或某物，作宾语的某人或某物属主语所有。
二、结构不同
there be + sb./sth. +时间/地点(副词或介词短语);sb./sth. + have +sb./sth. else
There are some children in the garden.花园里有几个孩子。
She has three cars. 她拥有三辆汽车。(汽车是属于她的)
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三、相同之处
1. 表示某物体在结构上“装有”“配备有”“固有”时，两者均可用。如:
A clock has a round face.= There is a round face on a clock. 钟面上有一个圆型的钟盘。
Each house on the street has a small yard.= There is a small yard in each house on the street. 这条街旁的每栋房子都有一座小花园。
2. 当have表示“包括”时，可以用 There be 替换。如:
A week has seven days. =There are seven days in a week. 一周有七天。
3. 当 have 表示“存在”时，可以用 There be 替换，如:
Our village has only one street.=There is only one street in our village. 我们村里只有一条街。
This country has rich resources, such as oil, coal and iron.=There is rich resources, such as oil, coal and iron, in this country 这个国家有丰富的资源，如石油、煤和铁等。
there be的非限定形式:
there be的非限定形式是there to be和there being，主要用来做介词或动词的宾语、主语或状语。如:
Have you ever thought of there being so many interesting films for you to choose from?没想到过有这么多有趣的电影供你选择吧?
John was relying on there being another opportunity. 约翰相信另有机会。
There being a bus stop so near my house is a great advantage. 有公交车停在离我房子这么近的地方是很大的优势。
There having been no rain, the ground was dry. 由于没有下雨，地上很干燥。
It’s unusual for there to be so few people in the street. (=It’s unusual that there are so few people in the street) 这条街上这么少的人是不寻常的。
It was too late for there to be any subways. 太晚了，不会有地铁了。
Would you like there to be a meeting to discuss the problem? 你们要开个会讨论一下这个问题吗?
I don’t want there to be a simple mistake in the article that I have written. 我不想我写的这篇文章中有错误。
I except there to be no argument about this. 我期限望对此事没有争论的。
注:there to be常做like, expect, mean, want, intend, prefer, hate等的复合宾语。
there be句式用于被动式:
■有通常情况下，there be句式中的 be表示“存在”。如:
There are numerous islands off the coast. 海岸边有许多岛屿。
There was a bed and a big wardrobe. 有一张床和一个大衣橱。
There was a rainbow in the sky. 天上有一道彩虹。
If there is any problem, let me know. 如果有什么问题可以通知我。
There is only one person I could approach. 只有一个人我可以去找。
There are in China over fifty minorities besides the Han nationality. 在中国除了汉族还有五十多个少数民族。
There is a lack of communication between the young and the old. 年轻人和老人之间沟通不足。
■但是，有时there be结构还可用被动式，这时be即变成了助动词，如:
There are now published thousands and millions of books every year. 现在每年出版上亿册书。
On the following day, there was held a splendid banquet. 第二天举行了盛大的宴会。