请用适当的词完成下面的短文。每空只能填写一个形式正确、意义相符的单词。

The moon is 【小题1】 away from the earth. We can only see a small moon with our own eyes on the earth. When we see a small part of the moon, we call it a crescent moon (新月). When we see the whole moon, we call 【小题2】 a full moon. That’s all people knew about the moon in ancient times. They even didn’t know the moon goes 【小题3】 the earth. But they thought that there might be life on the moon. However, in July 1969, scientists sent Neil Armstrong to the moon and found that there weren’t any 【小题4】 on the moon.

Have you ever heard of the satellite (卫星) called Early Bird, which was built by a group of scientists 【小题5】 14 countries? So far, a few satellites have been put into space and they helped people to 【小题6】 photos of the earth and other stars.

【小题7】 we know a lot about the moon and the earth now, people always ask the questions: Is there anyone out there in space? Are we alone? Our scientists haven’t got a clear answer 【小题8】. It is still one of the greatest mysteries (谜底) and some people think it will be a secret for 【小题9】 long time. But we believe we can 【小题10】 the problem some day.