Tony and Tina are very different. Tony likes music. Tina doesn't .Tony is an athlete. Tina isn't.

On the other hand , Tina like movies, but Tony doesn't .She is a good student, but he isn't .

Tony and Tina are brother and sister, but are they alike ? No, they aren't. They're very different .

重点：

1. athlete 名词 运动员
2. alike 相同的，相似的
3. 使用本单词时，不可置于名词前。
4. John and Peter are alike brothers. (错)
5. John and Peter are alike many ways.(对)
6. 约翰和彼得在许多方面很相似。
7. 本课主要介绍省略句的形成，及不定冠词a和an的用法。
8. 介词短语 on the other hand 的用法，及表示相对关系的名词之前省略冠词的用法。

Tony likes music. Tina doesn't .

Tony is an athlete. Tina isn't.

所谓省略句，就是省略两句重复的部分，使句子简单又不失清楚的含意。省略句形成的先决条件是：

a.两句的结构必须相同（时态及动词），第二句方可省略。

b.第一句若为肯定句，第二句则为否定句；第一句若为否定句，第二句则为肯定句。

形态有三：

a. be动词

He is a good studen. She isn't.

b. 助动词

He cannot do it . She can .

c. 动词

He likes music. I don't.

4. 一般而言可数名词若为单数形势时，之前要有不定冠词（a ,an）表示单数的概念。

a 置于辅音起首的单词前，而 an则置于元音起首的单词前。

This is a book .

There is an ox(公牛) there .