就一道选择题！急~！谢

C
因为哈勃太空望远镜永远都在地球大气层上方，所以不存在当不当的问题。所以A和B都不能用，只能是C

A
将来进行时 后面跟时间状语
while接进行时 且when和while同时出现时若表示时间状
while能干的when都能，而when能的有些while却不能
while和when同时出现时 选while的情况只有一个 表转折
如I like cats while he likes dogs.
至于because 语义变为Hubble已经上去了

选B，哈勃位于外太空时，给我们发送图片，WHILE强调它在外太空的过程中发送。

C

The Hubble telescope was launched into space by NASA on April 20,1990 at a cost of over a billion dollars. Right from the start there was trouble with the Hubble. The pictures it sent us were very disappointing because its main mirror was faulty! NASA is now going to put the telescope right, so it will soon be sending up four astronauts to repair it. The shuttle Endeavour will be taking the astronauts to the Hubble. A robot-arm from the Endeavour will grab the telescope and hold it while the astronauts make the necessary repairs. Of course, the Hubble is above the earth's atmosphere, so it will soon be sending us the clearest pictures of the stars and distant galaxies that we have ever seen. The Hubble will tell us a great deal about the age and size of the universe. By the time you read this, the Hubble's eagle eye will have sent us thousands and thousands of wonderful pictures.