蚯蚓在干燥的灰尘里和沙里，很快会死去，是因为（） A．体表_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

蚯蚓在干燥的灰尘里和沙里，很快会死去，是因为（）

A．体表粘液干燥，呼吸无法进行

B．体内水分蒸发，失水过多

C．灰尘阻滞了呼吸通道

D．干燥的环境中没有食物

答案

答案：A

题目分析：蚯蚓靠湿润的体壁进行呼吸，蚯蚓在干燥的灰尘里和沙里无法呼吸，很快就会死去，选A

填空题

A. with B. without C. medicine
D. fight against E. quickly

It is reported that 300 million people in China have eyesight trouble. More and more parents hope to save their children’s eyesight with   小题1:   or by correcting the ways that children read and sit. But in fact, one should start with the exercise on one’s feet. Here are three ways to save eyes.
First, don’t tie your shoes too closely. Try wearing comfortable and soft socks or walking  小题2:  socks and shoes at home. While you are travelling, try wearing cloth shoes in order to improve blood circulation(循环).
Second, walking on tiptoes(脚尖)is good for one’s eyesight. It can   小题3:  eyesight trouble.
Third, rope skipping can also be good for one’s eyesight. While skipping rope, one has to move 小题4:  , making both the brain and the eyes excited. It may also help make one grow taller.

填空题

有15名新生，其中有3名优秀生，现随机将他们分到三个班级中去，每班5人，则每班都分到优秀生的概率是______．（用式子表示即可）