1 . 根据文章内容，完成下列各句。

Have you heard of the sandstorm? It is a natural disaster. It often happens in the desert. A sandstorm is like a snowstorm. They both bring a lot of trouble to people. In sandstorms, the wind carries the sand. Sandstorms are different from other disasters(灾难). They come with a warning(前兆) but other disasters come without any warnings. So when you see that clouds have a dark colour, it means there is going to be a sandstorm.

If it doesn’t rain for a long time, sandstorms may happen. When there are sandstorms in cities, there will be no planes in the sky. It would be dangerous for the pilot(飞行员)to fly the plane because he cannot see clearly. There would also be more traffic accidents in the street. The sky is gray and people cannot see very far.

There are many deserts in Africa and Asia. Sandstorms often happen in these places. People can stop sandstorms by planting trees.

1. Sandstorm is a ________ and it often happens in the desert.
2. Both a sandstorm and a snowstorm bring ________ to people.
3. There is going to be a sandstorm if the clouds have ________.
4. Sandstorms may happen if it ________ for a long time. .
5. When sandstorms happen, the pilot cannot ________.