问题 单项选择题

机体调节酸碱平衡最迅速的途径是

A.肺脏

B.血液缓冲系统

C.细胞内外交换系统

D.肾脏

E.神经—内分泌系统

答案

参考答案:B

解析:
血浆中HCO3ˉ和H2CO3是主要的缓冲对,能有效缓冲外界原因所致的酸碱改变。

问答题
阅读理解

阅读理解。

      Fangfang, a 15-year-old Chinese girl, likes eating snacks very much. She prefers cream biscuits,

McDonald's food, KFC, and Beijing roast duck. Sometimes she eats two packages of biscuits a day. As a result,

she becomes overweight

      Today in China, there are many children like Fangfang. They like snacks. They don't eat enough healthy

foods like vegetables and fruit. It's very bad for their health. Poor eating habits are a serious problem.

      Health experts say that children should have healthy eating habits. First, they must eat regular meals and

begin with a good breakfast. Second, they should have different kinds of foods, such as fruit, vegetables, grain,

eggs, milk and meat and so on. Third, the children shouldn't eat too many snacks and fried foods. They are

delicious, but eating too much of them is unhealthy.

      If children do as the experts say, they won't become fat. They will be healthier. Students won't become

tired at school, and they will have enough energy to study well.

1. What does the underlined word "overweight" mean? [ ]

A. 聪明的

B. 懒惰的

C. 超重的

D. 痴呆的

2. Fangfang becomes overweight, because _____. [ ]

A. she is an American girl

B. she has a balanced diet

C. she likes eating snacks

D. she likes vegetables soup

3. What kind of food is good for your health? [ ]

A. Fast food.

B. Snacks.

C. Fried food.

D. Vegetables and fruit.

4. If students do as the experts say, they will ______. [ ]

A. become fatter and fatter

B. become more and more beautiful

C. have enough energy to study

D. be healthier and more tired

5. Which of the following is True? [ ]

A. Eating snacks is good for your health.

B. Fangfang doesn't like Beijng roast duck.

C. Fangfang comes from America.

D. Students shouldn't eat too much fried food.