going to choose; told him the plans and the __4__ they might get in. They then asked him if he was willing to be trained as an astronaut. "How could any man __5__ such an exciting job？" One of them said "Dangerous? Of course. It's dangerous __6__ most exciting"．

　　 The health and physical condition of __7__ was of course very necessary. __8__ those in very good health and physical condition were chosen.

　　 While being trained to be astronauts they went through many __9__. They studied the star and the moon and they also studied geology the science of rocks. This was necessary __10__ astronauts would have to look for rocks on the moon. They would try to find rocks which might help to tell the __11__ of the moon. They were all __12__ to fly in helicopters(直升机). These helicopters landed __13__ down to give them some experience of the way the spaceship would __14__ land on the moon. They were also taught the __15__ facts about the conditions in space. They learnt all the technical details of the spaceships and rockets. They visited the scientists and engineers who __16__ them. They visited the factories where they were __17__. They learnt how every __18__ of a spaceship and its instruments work. They also learnt every detail of ground－control __19__.

　　 In a word，to be chosen as an astronaut one must be in good health __20__ in science and good at piloting.

　　1．A.at　　　　　　　　B．between

　　C．of D．on

　　解析：美国航空航天管理局招收宇航员，年龄在20－35岁之间。between...and在......之间。

　　答案：B

　　2．A.experienced B．old

　　C．trained D．young

　　解析：招收人员做宇航员，所选人当然以技术熟练、擅长航空的人为主。

　　答案：A

　　3．A.None B．Few

C．Others D．They