问题 填空题

陆地上生活的生物一般都有防止水分散失的结构,如爬行动物具有角质______或______;昆虫具有______.

答案

陆生动物具有:①陆地气候相对干燥,与此相适应,陆生动物一般都有防止水分散失的结构. ②陆地上的动物不受水的浮力作用,一般都具有支持躯体和运动的器官,用于爬行、行走、跳跃、奔跑、攀援等多种运动方式,以便觅食和避敌. ③除蚯蚓等动物外,陆地生活的动物一般都具有能在空气中呼吸的,位于身体内部的各种呼吸器官. ④陆地动物还普遍具有发达的感觉器官和神经系统,能够对多变的环境及时做出反应.陆地气候相对比较干燥,所以陆生动物为了防止水分散失,以更好的适应陆地生活,一般有减少水分散失的结构,如:爬行动物有角质的鳞或甲,昆虫有外骨骼.

故答案为:鳞;甲;外骨骼

单项选择题 A1/A2型题
阅读理解

阅读理解。

     When we say older people shrink, we don't mean they become tiny enough to fit in your pocket! We

just mean that it's common for older people to become a little shorter over time. This kind of shrinking

can't be reversed, although people can slow or stop this process. But why does shrinking happen at all?

    Because of gravity (that force that keeps your feet on the ground) , cushions between the bones in the

spine (脊骨), get compressed (压缩), which makes a person lose a little height and become shorter.

    Another reason why some older people shrink is because of osteoporosis (骨质疏松). Osteoporosis

occurs when bone is broken down and not enough new bone material is made. Over time, bone is said

to be lost because it's not being replaced. Bones become smaller and weaker and can easily break if

someone with osteoporosis is injured.

     Older people - especially women, who generally have smaller and lighter bones to begin with-are

more likely to develop osteoporosis. As years go by, a person with osteoporosis can get small breaks in

bones that are called compression fractures. These breaks cause collapse of the spine and over time the

person with osteoporosis can become hunched over (驼背).

     Did you know that every day you shrink a little, too? You aren't as tall at the end of the day as you

are at the beginning. That's because as the day goes on, water in the disks of the spine gets compressed

due to gravity, making you just a tiny bit shorter. Don't worry, though. Once you get a good night's rest,

your body recovers, and the next morning, you're standing tall again!

     Smoking and drinking alcohol can make this problem worse. Want to do something right now to build

strong bones? I believe what I will say will help you.

1. Which of the following statements is true? 

A. For shrinking, people can do nothing about it.

B. If someone is injured, he will become shorter.

C. Women have smaller and lighter bones than men.

D. We aren't as tall at the end of the day as we are at the beginning.  

2. What should we do if we don't want to shrink faster?

A. We should try to reduce gravity.

B. We should be careful not to be hurt by others.

C. We should sleep as long as possible.

D. We should keep away from smoking and drinking alcohol.

3. What is the topic of the passage? 

A. How can we stop shrinking?    

B. Why do we shrink?

C. Some tips on how to keep tall.    

D. How to live a healthy life.

4. About osteoporosis we know that _______.  

A. gravity is one of the causes of osteoporosis

B. once our bone is broken down, osteoporosis will occur

C. women are more likely to develop osteoporosis

D. if we develop osteoporosis, we are more likely to be shorter

5. What will the author talk about in the paragraph to be followed?

A. Tell us how to grow taller.

B. Tell us how to become healthier.

C. Tell us how to avoid being shrinking.

D. Tell us what to do to have strong bones.