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 (the 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(受压骨折). 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.
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.

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.

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.

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

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.