定语
由来修饰名词或代词，常放在名词前面，也可以放在后面（叫后置定语）。由形容词、代词或相当于形容词的词或短语充当。
Your teacher will read out some sentences. 你们的老师将读出一些句子。
状语
用来修饰动词、形容词或副词。一般表示行为发生的时间、地点、目的、方式、程度等，常由副词、介词短语或相当于副词的词或短语等来表示，放在句末。
They plant trees in order to keep the soil on the hills. 他们种树以便把土壤保持在山上。
表语
表语是用来说明主语的身份、性质、品性、特征和状态的，表语常由名词、形容词、副词、介词短语、不定式、动词的-ing、从句来充当，它常位于联系动词（be, become, appear, seem等）之后。
一. 名词作表语
Africa is a big continent.
非洲是个大洲。
That remains a puzzle to me.
这对我还是个难题。
二. 代词作表语
What’s your fax number?
你的传真号是多少？
三. 形容词作表语
I feel much better today.
我今天感觉好多了。
四. 数词作表语
She was the first to learn about it.
她是第一个知道的人。
五. 不定式或ing形式作表语
Her job is selling computers.
她的工作是销售电脑。
Our next step was to get raw materials ready.
我们下一步是把原料准备好。
六. 介词短语作表语
The patient is out of danger.
病人脱险了。
I don’t feel at ease.
我感到不自在。
七. 副词作表语
The sun is up.
太阳升起来了。
I must be off now.
现在我得走了。
八. 从句作表语
This is what he said.
这就是他所说的话。
不定式作表语
作表语的不定式短语通常是说明主语的内容，这时主语通常是如下名词：
hope, idea, job, plan, wish, aim, purpose, thing, business
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The purpose of new technologies is to make life easier, not to make it more difficult.
新技术的目的是使生活更便利，而不是更繁琐。
Her wish is to become a singer.
她的愿望是当一名歌手。
Our plan is to finish the work in two weeks.
我们的计划就是在两星期内完成这项工作。
表语从句
在句子中起表语作用的从句叫做表语从句。表语从句的引导词和主语从句的引导词相同。
What the police want to know is when you entered the room.
警察想知道的是你什么时候进的房间。
The trouble is that we are short of funds.
困难是我们缺乏资金。
This is what we should do.
这是我们应当做的。
That's why I want you to work there.
那就是我要你在那儿工作的原因。
His first question was whether Mr. Smith had arrived yet.
他的第一个问题是史密斯先生到了没有。
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as if, as though, because也可用来引导表语从句。
She seems as if she had done a great thing.
她看起来好像做了一件大事。
It is because you eat too much.
那是因为你吃得太多了。
ing形式作表语
ing形式作表语表示泛指意义的动作，不定式作表语表示一次性的动作。
My hobby is growing flowers.
我的爱好是种花。
My favourite sport is playing tennis.
我喜爱的运动是打网球。
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比较：
What I am going to do is to play tennis this afternoon.
我今天下午要做的事是打网球。
ing形式作表语：注意事项
在句型"主 + 系 + 表"中，若主语和表语都是非谓语形式时，主语和表语要取得一致。如：主语
是ing形式表语也应是ing形式，主语是不定式时表语也应是不定式。
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Seeing is believing.
To see is to believe.
眼见为实。
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(误) Seeing is to believe.
ing形式作定语
ing形式可以作名词的前置定语，ing形式短语作后置定语。
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ing形式作前置定语
a swimming pool
a teaching method
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ing形式短语作后置定语
Do you know the man standing at the entrance?
你认识站在入口处的那个人吗？
There were a lot of people boating on the lake.
湖上有许多正在划船的人。
虚拟语气：表语从句
主语是idea, notion, proposal, suggestion, request等名词时,
作表语从句的动词为原形动词或should+原形动词。
My suggestion is that we (should) go and help him.
我的建议是我们应该去帮助他。
Our only request is that this should be settled as soon as possible.
我们唯一的请求就是尽快解决这个问题。
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