为什么要有定语状语表语补语

这是对句子结构进行分析所需要。即不同的词类做什么语法作用，它们的结构和序列又是怎么样的，这些需要进行科学地归纳出规律。

1、定语：限定名词/代词的词语。位置可在名词的前或后。能作定语的词语有：

形容词：Victoria is a beautiful city in Canada.

名词：This is an apple tree.

数词：There are thirty teachers in our school.

介词短语：Tom is reading an article about gardening.

不定式短语：She is always the first to come to the office.

分词短语：China is a developing country America is a developed country.

动名词短语：The teaching plan for next term has been worked out.

定语从句：The man who is shaking hands with my father is a policeman.

Liquid water changes to vapor， which is called evaporation.

2、状语：修饰动词的词语（也修饰形容词、副词或句子）。位置比较灵活。状语的种类有十一种：时间、地点、方式、原因、目的、结果、比较、让步、条件、程度、伴随状语。能作状语的词语有：

副词：He run very quickly.（方式状语）

形容词：He lay in the bed， awake.

现在分词短语：He is in the room， making a model plane.（伴随状语）

Walking in the street， I met my daddy.（时间状语）

Not knowing the way to the school， they are worried. （原因状语）

过去分词：Seen from space， the earth looks blue. （条件状语）

He left the room， followed by his wife.（伴随状语）

The professor is sitting in a chair， surrounded by students. （伴随状语）

不定式短语：Tina is proud to have passed the final exam.（原因状语）

I need a dictionary to learn English well.（目的状语）

介词短语：She has lived in the city for six years.（时间状语）

名词短语：Wait a minete.（时间状语）He works hard day and night.（方式状语）

状语从句：I didn't attend the party because it rained.（原因状语从句）

He got up early so that he could catch the first bus.（目的状语从句）

Peter will go there if it doesn't rain.（条件状语从句）

3、补语：补充或说明其前面的名词的词语。分宾语补语和主语补语。宾语补语：有些及物动词，除了要有宾语，还要在宾语后面跟上宾语补语，构成复合宾语，才能使句子意思完整。如果这类句子变成被动语态，宾语成为主语，则原宾补相应变为主补。做补语的词语有：

名词：His father named him Daming.

形容词：They painted the wall white.

副词：Let the fresh air in.

现在分词：I heard Tom singing in the classroom.

过去分词：I have my house repaired.

不定式：My mom wants me to be a doctor.

从句：We will soon make our city what your city is now.

现在分词做主补：Jean was heard singing by me this morning.

介词短语做主补：Everything was found in good order by us.

4、表语：表达主语的特征或者性质的词语。位置在系动词后面（倒装除外系动词有六类）。作表语的词语有：

名词：Our Math teacher is a Canadian.

代词：Is it yours?

形容词：The weather has turned cold.

副词：Time is up. The class is over. I am off.

现在分词：The speach is exciting.

过去分词：I am excited.

动名词短语：My hobby is playing table tennis.

不定式短语：My job is to tach English.

介词短语：The machine must be out of order.

表语从句：The truth is that he has never been abroad.

5、它们的从句：用一个句子做上述成分（“语”），就是对应“语”的从句。这个从句可以含有自己的从句，这就形成了从句的嵌套。举例说明（斜体加粗部分为从句，但下面的从句里都没有嵌套从句）：

限定性定语从句：The manwho is shaking hands with my father is a policeman.

非限定性定语从句：Liquid water changes to vapor， which is called evaporation.

原因状语从句：I didn't attend the party because it rained.

目的状语从句：He got up early so that he could catch the first bus.

条件状语从句：Peter will go thereif it doesn't rain.

表语从句：The truth is that he has never been abroad.

补语从句：We will soon make our city what your city is now.（注：这是宾语补语从句。很少有人讲“补语从句”）