如何选择牙刷？

当前的大学生作为一个特殊的社会群体，有着自身鲜明的心理特点，大学生情绪的特点主要有（）

A、情绪活动趋于丰富

B、情绪的冲动性

C、情绪的双极性、摇摆性

D、情绪的压抑性

     Your body, which has close relation(关系) with the food you eat, is the most important thing you

own. So it needs proper treatment(对待) and proper nourishment(营养).

     The old saying “An apple a day keeps the doctor away” is not silly as some people think. The body needs fruit and vegetables because they contain vitamin C (维生素C). Many people take extra(额外的) vitamins in the form of pills(药丸), believing that these will make them healthy. But a good diet is made up of nourishing food and this gives all the vitamins you need. The body doesn’t need or use extra vitamins. So why waste money on them?

     In the modern western world many people are too busy to care about eating  properly. They throw anything into their stomachs, eating hurriedly and carelessly. The list of illness caused or made worse by bad eating habits is frightening.

1. The old saying in the passage tells us that_______.

A. the apple is the best among all kinds of fruits.    

B. apple can take the place of doctors.

C. eating apples regularly (有规律的) does lots of good to our health.  

D. an apple is a sure cure for illness.

2. In the second paragraph the writer tries to let us know______.

A. our bodies need food or we can't live.      

B. often eating apples is a good habit.

C. taking extra vitamin pills is completely useless.

D. a good diet is very important to our health.

3. From the passage we can draw a conclusion(得出结论) that if we want to keep healthy, we should

______.

A. only eat an apple a day.          

B. eat properly.

C. take as many vitamins pills as possible.

D. throw food into our stomachs slowly and carefully.

SF6气体是一种无色、无毒、不燃、绝缘强度高、灭弧能力强的惰性气体，它的去游离速度比空气快100倍

简述水流流速、颗粒大小与碎屑物质在流水中搬运与沉积的关系。

昏迷、休克伤病员保持平卧，下肢略抬高，保持呼吸道畅通，头部应（），以防呕吐物、分泌物误吸入呼吸道。

A.放平

B.面部朝上

C.向上仰

D.偏向一侧