In space, the slightest touch against something may send you flying ________ the opposite direction．

1. A.
   to
2. B.
   toward
3. C.
   in
4. D.
   for

 In space technology, there is no doubt that China is ________any other Asian country.

A. in return for    B. ahead of      C. in exchange for      D. in case of

_______ in space by ordinary citizens will be common.

　 A. Travelled　　　 B. Travel　　　　　　　 C. Travels　　　　　　 D. Travelling

_______ in space by ordinary citizens will be common.

　 A. Travelled　　　 B. Travel　　　　　　　 C. Travels　　　　　　 D. Travelling