I think that he is old enough to join the army.

5、宾补：英语中有少数及物动词后除了接一个宾语外，还必须有一个宾语补足语对宾语进行补充说明，这样才能使句子的意义完整，这类动词被称为"复合及物动词"，常见的动词有：make, consider, find, get, have, let等。

The boss made us work 14 hours every day.

We found the dog lying on the ground.

We painted our house white.

We found him killed the next morning.

6、定语：用来修饰限定名词或代词的词、短语或从句。通常由下列结构充当：形容词、分词、名词、代词、数词、不定式、动名词、介词短语等。

She is a beautiful girl.

My book is old.

More than 30 students in our class are from abroad.

He is the first to come and the last to leave.

The teaching building is under construction.

The girl in white is my sister.

7、状语：用来修饰动词、形容词、副词或整个句子，说明动作或状态特征的句子成分。通常由副词、介词短语、不定式、分词、名词、形容词或状语从句等充当。

She used to sit for hours quietly.

He has lived in the countryside for 20 years.

The tree is too tall for the boy to climb up.

Encouraged by the teacher, she made up her mind to learn English well.

Wherever you go, whatever you do, I will wait for you.

8、同位语（appositive）对前面的名词或代词做进一步的解释，通常由名词、数词、代词或从句来充当。

This is Mr. Zhou, our headmaster.

The question who should do the work is still in discussion.

9、插入语（parenthesis）：对一句话作一些附加的解释；通常由形容词、副词、介词短语、动词不定式、现在分词或从句来充当。

To be frank, I don't quite agree with you.

第三节 并列句

一、概念：有两个或两个以上的简单句连在一起，构成的句子叫做并列句。

例：He made a promise, but he didn't keep it.

*： 1、并列句中两个简单句相互之间没有结构的所属关系，只是在语意上存在一定的联系。

2、并列连词的确定取决于分句之间的语意关系

二、类型：1）顺承并列句；2）转折并列句；3）选择并列句；4）因果并列句；5）条件或结果并列句

1、顺承并列句：表示两个同等的概念，常由：and, not only...but also等连接

　　例：They talked happily, and they forgot to cook supper.

Not only did the students sing, but also the teacher sings.

2、转折并列句：表示两个分句在语意上转折。常由：but, while, yet, nevertheless等连接

例：He worked hard, yet he failed.

Some problems are easy while others are difficult.

3、选择并列句：常由or，either...or, otherwise等连接

例：Either you leave this house or I will call the police.

I must work much harder, otherwise I can't catch up with the other classmates.

4、因果并列句：常由for, so, therefore 等连接

例：It was late, so we went home.