3. Why do astronauts have to grow their own food on long-distance space exploration?

　A. Because fresh food is good for their health.

　B. Because they can have what they like during the trip.

　C. Because they can learn how to grow crops on Mars.

　D. Because they are unable to take enough food with them.

4. Why is it unusual for the future ＂astroplants＂?

　A. They will grow without dirt, sunlight or gravity.

　B. They will be planted by astronauts.

　C. They will grow in space.

　D. They will be grown without water.

5. According to the passage, the further we explore the space, ___________.

　A. the more difficulty we will have in growing ＂astroplants＂

　B. the more water ＂astroplants＂ will need to grow

　C. the more important space farming will become

　D. the less ＂Earth food＂ will be carried

【答案】

　　【语篇解读】本文是一篇说明文，主要介绍了如何发展深厚的友谊。作者在文中给出了几条建议。

II. 阅读理解