书面表达
近20年来，各方面调查表明青少年体质的下降令人担忧。请你以“How to Keep Healthy？"为题，写一篇60到80词的短文，说说你的看法和建议。
要求：主要包括以下内容，可以适当发挥。开头已给出，不计入总词数。
1. 体质下降的原因，如：eat too much junk food，have too much homework. .
2. 合理的健康建议，如：some useful advice，should do more exercise，eat a balanced diet（饮食平衡），enough sleep. . .
How to Keep Healthy？
Nowadays students' physical fitness is declining（体质下降）year by year. I think there are some reasons.
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