［选修4：中外历史人物评说］

材料  颜真卿“少勤学业，有词藻，尤工书”。唐玄宗时登进士甲科，历官侍御史等职，因为人刚直，不附权臣杨国忠，出为平原太守。安史之乱爆发，其以平原一郡独撑河北危局良久。后任刑部尚书，“军国大事，知无不言”，“累进封鲁郡公”。藩镇李希烈反，颜真卿前往安抚，面对叛军“不能屈节，当自烧”的威胁，愤然赴火。后被叛军杀害，终年77岁。朝廷赠司徒，谥“文忠”。颜真卿“立朝正色，刚而有礼，非公言直道，不萌于心。天下不以姓名称，而独曰鲁公”。史书称赞他“富于学，守其正，全其节，是文之杰也”。

唐人重书法，“工书”者甚众，颜真卿“善正、草书，笔力遒婉”，尤为后人所推崇。欧阳修得其所书残碑，赞曰：“颜公书如忠臣烈士、道德君子，其端严尊重，人初见而畏之，然愈久而愈可爱也……虽其残缺不忍弃之。”

——据《旧唐书》等

    Here are some tips about how to keep healthy.

1) Healthy food is important. If you want to keep healthy, eat lots of fruit and vegetables. Don't eat much meat.

2) Water is important. Drink water every day. Milk is good for you, too. Don't drink sweet drinks.

3) Exercise is important. You can ride your bike or play soccer. Going swimming is a good idea.

4) Clean air is important. If you are free, you can go to the park and enjoy clean air.

5) Your teeth are important. You should brush your teeth twice a day.

6) Sleep is important, too. Go to bed early. Don't stay up late, or you will feel sleepy.

下列人体消化液中，含消化酶种类最多的一组是（    ）