How to Use Our Brain
1．人腦的重要性及作用。
2．如何科學用腦。
[寫作導航]先寫大腦的特性和作用(複雜、智慧型的器官，使人區別於動物等)；再寫大腦越用越靈，但過度使用也會出問題，為第三段作鋪墊；第三段從兩方面說明如何合理用腦：一是勞逸結合，手腦交替；二是從科學的角度，利用數據，說明過度用腦可能給大腦帶來的傷害。
[範文]
Human brain is the most complex and intelligent mechanism in the world. It is the major factor that distinguishes man from animals. With our brain we get to know the world and make a good use of the world to our benefit.
Our brain is a product of constant use through millions of years. Other things can be used up, but used properly, our brain can never be exhausted. In fact, the more we use it, the more capable and efficient it will become. Excessive use of the brain, however, will causea lot of problems. So it is useful to know how to use our brain wisely.
First, handwork or physical labor is good exercise as well as rest for our brain. Doing handwork and brain work alternatively can help develop both our brain and hands. Secondly, we should avoid doing brainwork for long hours on end. The brain, though 3% of the body weight, when at work, consumes 20% of the oxygen carried by 16% of the blood in circulation. A long period of brainwork may cause, through lack of bodily activity, slow blood circulation and inadequate oxygen supply to the brain, resulting in inefficiency and possible damage to the brain.