英语学习之系动词be用法
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。下面是小编给大家分享的系动词学习内容，大家可以作为学习的参考。
英语系动词be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.
(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.
系动词可接哪些词语作表语：
连系动词后的表语通常是名词和形容词，有时也可以是代词、数词、副词、介词短语、不定式、动名词、从句等。如：
1. 用名词作表语。如：
Translation is an art. 翻译是一种艺术。
Beijing is a beautiful city. 北京是一座美丽的城市。
2. 用形容词表作语。如：
Traveling is interesting but tiring. 旅行是有趣的，但是使人疲劳。
Every hour and every minute is important. 每一小时，每一分钟，都很宝贵。
3. 用代词作表语。如：
My idea is this. 我的想法是这样的。
Money isn’t everything. 金钱不是一切。
His latest play is nothing. 他最近出的那个剧本毫无价值。
4. 用数词作表语。如：
Tom is 14. 汤姆14岁。
Last check-in time is 20:15. 最后检票时间为20点15分。
The average of letters received each month is 3,000. 每月平均收到信件3,000封。
5. 用副词作表语。如：
The secret is out. 机密泄漏了。
Sales are down. 销售量下降了。
She is off on Saturday. 她星期六不工作。
6. 用介词短语作表语。如：
Dinner is at six. 6点钟开饭。
I hope he is on time. 我希望他准时。
Martha still is in hospital. 马撒还在医院里。
Diana was with the children. 戴安娜和孩子们在一起。
You look like your sister. 你模样像你姐姐。
7. 用不定式作表语。如：
His goal is to be a doctor. 他的目标是当医生。
My duty is to protect my sisters. 我的职责是保护我的妹妹们。
My advice to you is to speak the truth. 我对你的忠告是讲真话。
My dream is to travel around the world. 我的梦想是环游世界。
8. 用动名词作表语。如：
Her hobby is growing roses. 她的爱好是种植玫瑰。
His job is looking after sheep. 他的任务是看羊。
My favorite sport is swimming. 我最喜欢的运动是游泳。
9. 用从句作表语。如：
That’s what we are here for. 我们来这里就为了这个。
The question is how he did it. 问题是他是如何做此事的。
That’s where I first met her. 那就是我第一次遇见她的地方。
The trouble is that I have lost his address. 麻烦的是我把他的地址丢了。
副词可用于系动词后作表语吗：
原则上说，用于系动词后作表语要用形容词，而不是副词。如：
他的英语很好。
误：His English is very well.
正：His English is very good.
这饭菜闻起来真香。
误：The dinner smells deliciously.
正：The dinner smells delicious.
但在以下情况，副词可用作表语(且主要是用于系动词be后作表语)：
1. 表示地点或位置的少数副词，如here, there, upstairs, downstairs, abroad, back等。如：
He asked if anyone was there. 他问那儿是否有人。
Are the children back yet? 孩子们回来了吗?
Neither of them is here. 他们俩都不在这里。
She was abroad all last summer. 她去年整个夏天都在国外。
If he was downstairs, why didn’t he answer the bell? 他要是在楼下，为何不开门呢?
2. 与介词同形的小品词有也可用作表语，如in, on, off, out, by, away, behind, up, down, over, through, around, round, below, inside, outside 等。如：
Make sure the lid is on. 确信要把盖子盖上。
The engagement is off. 婚约取消了。
The taxi is outside. 出租车在外面。
The grocery was below. 杂货店在下面。
The level of unemployment is down. 失业率在下降。
I phoned Sally but she was out. 我给萨莉打电话，可是她不在。
He hid the money when nobody was by. 附近没人时他把钱藏了起来。
By the time we arrived the meeting was over. 我们到达时，会议已结束了。
He was left in charge of the shop while the manager was away. 经理不在时，他负责这个商店。
用于进行时态三类系动词：
英语的系动词通常不用于进行时态，但以下几类有时可以这样用：
1. 状态系动词
表示状态的系动词 be 与动态形容词连用时，可以用于进行时态，表示特定的表现。如：
She is being very annoying this evening. 她今晚很烦人。
Your brother was being a fool yesterday. 你兄弟昨天真蠢。
I was being very careful. 我当时非常小心。
2. 感官系动词
感官系动词feel(感觉), look(看起来)有时可用于进行时态。如：
I’m feeling fine. 我现在感觉良好。
I’m feeling a bit lonesome. 我感到有点寂寞。
I’m glad you’re feeling so much better. 我很高兴你感觉好多了。
Why is she looking so sad? 她为什么愁容满面?
My boy is not looking very well. 我的孩子气色不太好。
但是，当feel表示人自身的感觉时，可用于进行时态;但当它表示事物给人的感觉时，它不能用于进行时态，如以下各句不用进行时态：
Silk feels soft and smooth. 绸子摸起来柔软光滑。
Silk feels soft and smooth. 绸缎摸起来柔软光滑。
It felt pleasant going to work. 上班去的感觉很愉快。
3. 变化系动词
变化系动词become, grow, get, go, run 等有时可用于进行时态强调变化的进程。如：
The weather is getting colder. 天气渐冷。
Her hair is going grey. 她的头发日见花白。
Our supplies are running low. 我们的供应品不多了。
The pollution problem is growing serious. 污染问题日见严峻。
It was becoming cold, so we lit the fire. 天气变冷了，于是我们就点起了火。