写作思路：从文章的写作目的、中心主旨入手，以使文章中心思想鲜明、深刻地表现出来，正文：
How to prevent the flu
如何预防流感
These days,many people become sick,especially have the flu.Every year,when the season changes,the flu spreads quickly.But how to prevent the flu?And what should we do then?
这些天，许多人生病了，尤其是流感。每年，当季节变化时，流感会迅速传播。但是如何预防流感呢？那我们该怎么办？
First,we must do enough exercise everyday.We may play sports ,such as walking,running,doing morning exercises,playing ball games,and so on.Doing sports can help build up our bodies.
首先，我们必须每天做足够的锻炼。我们可以做运动，比如散步、跑步、做早操、玩球类运动等等。做运动可以帮助我们强身健体。
Second,we'd better keep our rooms clean and the air around us fresh.We should often tidy our rooms and sweep or mop the floor.And we must often open the windows and let the fresh air in.
第二，我们最好保持房间干净，周围的空气新鲜。我们应该经常整理房间，扫地或拖地。我们必须经常打开窗户，让新鲜空气进来。
Third,we should often wash our hands with the move water,if permitted.And we'd better have a bath as often as possible.Of course,we have to often change our clothes,too.In this way,the germs can't come into the body through the skin.
第三，如果允许，我们应该经常用流动的水洗手。我们最好尽可能经常洗澡。当然，我们也要经常换衣服。这样，细菌就不能通过皮肤进入体内。
Fourth,we'd better keep away from the crowded places,such as the hospital,the big supermarket,business center and so on,Because the air there isn't fresh enough.We may easily catch all kinds of infections there.
第四，我们最好远离拥挤的地方，如医院、大超市、商业中心等，因为那里的空气不够新鲜。我们在那里很容易感染各种传染病。
Next,we have to drink enough water every day.At this time of year,the air is always quite dry.There's little rain and it blows strongly.Many people feel thirsty easily.So we'd better drink 1500milliliter water every day,or we'll get xick in different ways.
接下来，我们必须每天喝足够的水。每年的这个时候，空气总是很干燥。很少下雨，而且风很大。很多人很容易口渴。所以我们最好每天喝1500毫升的水，否则我们会以不同的方式中毒。
Finally,it's better to go to bed early and get up early.There's a famous saying which says:"Early to bed and early to rise makes you healthy,wealthy and wise."Having enough sleep can help make us keep healthy.
最后，还是早睡早起比较好。有一句名言说:“早睡早起使你健康、富有和聪明。”
Good health is more important than wealth.Hope you keep healthy every day!
充足的睡眠可以帮助我们保持健康。
健康比财富更重要。希望你每天都保持健康！