热点二：甲型流感：（1）
假如你是李华，你学校内有人得了猪流感，正在接受治疗，你校学生非常害怕，请你写一篇短文谈谈如何预防猪流感？
1. 平时外出戴口罩，少去人群集中的公共场所, 避免接触病人等。
2. 勤洗手，保证充足睡眠，多锻炼多运动等。
3. 词数: 120字左右
4. 文章的开头已给出, 不计入总词数。
参考词汇: 猪流感swine flu; 口罩 face mask.
Swine flu has come to our School! However, there is no vaccine to protect its virus. How do we protect us from it?
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Swine flu has come to our School! However, there is no vaccine to protect its virus. How do we protect us from it?
We advise that you should wear face mask and avoid going to the crowded place when you go out. We remember not to be in close contact with the patients infected with swine flu. On the other hand, the best way to stay away from this virus is to wash your hands often, and make sure that you have enough sleep. At the same time, we should do more exercise so that we can build up our body.
We are sure that we must overcome the threat against swine flu as long as we take proper measures and insist on taking exercise every day.
静是禅。 
净是禅。
仿佛冥冥命运中赐予我一瞬得天独宠的美丽，让我的心静在蝶翼的翩然中，让我的魂净在蝶衣的绮梦中；使我的生命禁得住岁月最苛刻的吟读，让我在清晨花瓣的露珠上B（构筑 构造）水晶的房屋，安置我们的芳香的邂逅。
不期而遇的蝶啊。
颤动的双翅萌动一树花蕾，潮涌一河春汛。
我将以心为桥，走进春天的脉络，将一朵最美的花融入生命。
由此我住进幸福的春天，永远的春天。
段在文中有何作用？为什么单独成段？