A
Dust storms appear when strong wind blows sand and dirt from a dry surface. Strong dust storms can cause injuries and deaths, so it's necessary to know what to do when you come across them.
Be careful of dust storm warnings.
Dust storms are most likely to happen on hot summer days, so listen to the local TV or radio before traveling in hot, dry conditions, and consider changing or giving up your trip if dust storms are predicted (预测). Roadside signs may also be able to warn you of dust storm danger.Be prepared.
If you are in an area where storms happen often, carry a mask to keep out of dust and dirt from your face, and take eye protection to protect your eyes. A supply of water is also necessary.
Go beyond the storm.
If you see a dust storm from some distance, and you are in a car, you should try to escape from it. Some dust storms can travel at more than 75 miles per hour, but they usually travel much slower. However, it is not advised for you to put yourself in danger by driving at high speed.
Stay inside.
Do not move about in a storm, as you will not be able to see hidden dangers in your way. So if you're in a house，stay inside.
Protect yourself from flying objects.
Cover as much of your body as possible. A dust storm's high wind can carry heavy objects. If you find yourself without shelter, try to stay low, close to the ground, and protect your head with your arms or a backpack.
【语篇解读】 本文为说明文，是自然灾害类文章。主要介绍了遇到沙尘暴时应采取的措施。
21．What does Paragraph 4 mean?
A．Dust storms usually travel much slower than cars.
B．Don't be so worried about dust storms in the distance.
C．You shouldn't drive at a dangerous speed to escape from dust storms.
D．Driving faster than the dust storm is the most important thing.
答案与解析：C 细节理解题。根据第四段的第一句“If you see a dust storm from some distance, and you are in a car, you should try to escape from it.”和最后一句“However, it is not advised for you to put yourself in danger by driving at high speed.”可知，遇到沙尘暴时，不应该高速驾驶逃离。故选C。
22．We can learn from the passage that ________.
A．it is dangerous to travel on hot summer days
B．dust storms usually come from far away
C．people should stay indoors when a dust storm comes
D．small objects blown by a storm's wind cannot hurt people
答案与解析：C 细节理解题。根据第五段可知，沙尘暴来临时，应尽量待在室内避免隐藏的危险。故选C。
23．Which may NOT really be needed when you come across a storm?
A．A pair of glasses. B．A mask.
C．A bottle of milk. D．A travel guide.
答案与解析：D 推理判断题。根据第三段可知，如果置身在常发生沙尘暴的地域，你应该准备口罩、眼镜和水等物品，不需要旅行指南。故选D。
