已知△ABC中，AB=3，BC=1，tanC=3，则AC等于______．

阅读理解。

     Do you know about the flu? The flu usually spreads quickly. In winter, lots of people may get the flu.

If you get sick, do you know what to do? Here are some tips.

     Drink lots of water. Water is good for your body when you get the flu.

     Get plenty of sleep. If you can't sleep, you can listen to music, watch a movie or read a book to relax

yourself.

      If you feel serious, ask your parents to take you to see a doctor. But don't take medicine until you see a

doctor.

     Wash your hands often! You certainly don't want to spread the flu to anyone else. Also, don't share cups

and eating utensils (用具), like forks, with other people.

      Most people will get better without seeing a doctor, but it will take them about a week to get well. If you

have a high temperature for more than a few days, call your doctor at once.

1. The underlined word "tips" means ______ in Chinese.

A. 末端

B. 建议

C. 小费

D. 垃圾

2. What should you drink to keep healthy?

    _____________________________________________________

3. How can you relax yourself if you can't sleep?

   ______________________________________________________

4. Must you see the doctor if you don't get the serious flu? 

   ______________________________________________________

5. :将文中画线的句子译成汉语。

   ______________________________________________________

二项分布应用的变量是（）

二项分布应用的变量是

A.数值变量

B.定量变量

C.等级变量

D.二分类变量

E.多分类变量

实验室要配制200g质量分数为10%的食盐溶液，现提供以下物质选择使用：

足量的食盐固体、足量的水、160g质量分数为5%的食盐溶液、100g质量分数为20%的食盐溶液．

（1）请你设计出两种配制方案，写出具体计算步骤．

方案一：______；

方案二：______．

（2）如果郁郁同学按你设计的方案一配好食盐溶液，其质量分数小于10%．请你帮他分析实验操作中可能有哪些误差？

因吵架后突然发生耳鸣、耳聋2日。现听力明显减退，耳鸣如雷声，耳闭塞感。伴有恶心、眩晕，头痛，烦躁易怒，失眠，口苦，咽干，大便干结，小便黄。检查见两目筋脉红赤，舌边红，苔黄，脉弦数。辨证多属（）

A.肝火扰耳证

B.痰火壅耳证

C.湿热熏耳证

D.阴虚阳亢证

E.风痰扰耳证

釉面砖在施工挑选时应注意（）。

A.颜色

B.比重

C.薄厚

D.吸水率