阅读理解
In northern China during spring, big sandstorms often make trouble for people. When the sky is dark with sand, buses and cars all move much more slowly. Sometimes, people can't even see for 20 metres.
Sandstorms usually happen in spring. Big sandstorms happened in more than 10 provinces in northern China last year. More than 70 million people have had problems in those places because of the sandstorms.
People in southern China don't have to worry about this kind of bad weather. Most of the sand comes from the north of China. In northern China, lots of places have few trees and don't get much rain. People there have been cutting down too many trees. When there aren't many trees, the ground can't keep enough water. Over the years, the ground dries up and turns to sand. When spring comes and the ice melts (融化), the ground becomes looser (更松散的). Strong winds take the loose sand into the sky.
Sandstorms are bad for people's health. If people take in too much sand, they could cough or have asthma (哮喘).
Sandstorms also give farmers lots of problems. Sometimes their sheep get lost in the storms and never get back home. The winds alsotear downfarmers' houses.
What can you do to stop sandstorms? Here's an idea: Ask your parents to help you plant some trees this spring.
If you see people cutting down too many trees, tell them about the dangers of sandstorms, and ask your government to stop them from cutting.