III．教学重难点

1.Enable the students to grasp the usages of such important new words and expressions as exist, puzzle, in one's turn, prevent...from...,in time

2. Enable the students to grasp the usages of sentence patterns such as :

Whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.

IV. 教学过程

Direct students to conclude the usage of the key words and sentence patterns by reading example and analyzing its rules.

1. system (n)

1) a set of connected things that work together for a particular purpose.

【例】I decided to install (安装) a central heating system.

我决定安装中央供暖系统。

Lack of sleep can be hard on the system of your body.

缺乏睡眠对身体有害。

The system requirements for this program are listed below.

使用该程序所需要的系统要求列举如下。

2）a method of organizing or doing things.

【例】 a legal system: 法律体制

【短语：】

the system: rules that decide how a society, country, or organization should operate and that can not be changed even though they seem unfair to you. 现行体制，现成制度。

You can't beat the system. 你必须按规矩办事。