1 . The tooth is the hardest part of your body. Your teeth help you in many ways. For example, they can help you talk. They can also help you have a great smile. And the most important job of your teeth is to chew (咀嚼) your food. But do you know how your teeth grow?

When you are born, you don’t have any teeth. About 8 months later, small teeth begin to appear one by one. These teeth are called baby teeth. They are also called milk teeth. You won’t have baby teeth forever. They usually begin to fall out when a child is about 6 years old. Then, permanent (永久的) teeth begin to appear. These teeth are larger and more powerful. Most people will have 28 permanent teeth by the time they are 12 years old.

For some people, four more permanent teeth arrive by their 25th birthday. They are called wisdom teeth (智齿). But these teeth don’t make you smart! Sometimes they bring you pain. If a wisdom tooth brings you too much pain, you should go to a dentist (牙医) and have it pulled out.

1. Which part of your body is the hardest?

A．The nose.

B．The tooth.

C．The leg.

D．The hand.

2. The most important job of your teeth is           .

A．to prepare food

B．to cook food

C．to chew food

D．to protect food

3. What does the underlined word “They” in Paragraph 2 refer to?

A．Baby teeth.

B．Adult teeth.

C．False teeth.

D．Big teeth.

4. How many permanent teeth will most people have by the time they are 12 years old?

A．22.

B．24.

C．26.

D．28.

5. According to the text, what should you do if a wisdom tooth brings you too much pain?

A．Go to a dentist and have it brushed.

B．Go to a dentist and have it pulled out.

C．Go to a dentist and have it cleaned.

D．Go to a dentist and have it examined.

2 . Ways to protect eyes from screens

Too much screen time may cause serious eye strain (眼疲劳) and even a sharp decline of eyesight. That's a big problem a lot of people are faced with nowadays, especially those who work on a computer. The following tips may be helpful.

Get regular eye tests

Experts recommend having a comprehensive eye exam every year to detect (探测) problems before they develop. During this test, you should tell the doctor how often you use your phone and your computer.     1     Tell your doctor about it, and your eyes can be tested more accurately at that distance.

Give your eyes space

    2     Studies on computer-related eye strain suggest that screens should be no closer than 40 cm from your face. If this makes it hard for you to read, consider increasing the size of the text rather than moving the screen closer.

Take breaks

This may not always be practical if you're quite busy, but it's important not to stare directly at a screen for too long.     3     While surveys have shown that many office workers take no more than half an hour a day away from their computer, it's recommended that you take a 15-minute break after every two hours spent at your screen.

    4    

Staring at a screen continuously for hours on end may make it difficult for you to focus. To avoid this, many eye experts recommend the “20-20-20 rule” — looking away from your phone/computer screen every 20 minutes and focusing on an object at least 20 feet away for at least 20 seconds. The science behind his trick is that looking at objects at a distance relaxes the focusing muscle in the eye.     5    

A．Exercise your eyes.

B．Give your eyes a chance to rest.

C．Make your screen more eye-friendly.

D．Studies show it's an effective way to reduce tiredness.

E．You should also measure the distance from your eyes to your screen at work.

F．The closer your phone/computer screen is to your eyes, the harder they have to work to focus.

G．Make sure that you use your phone or computer in a room where the lighting is bright enough.