Today there are more than 100 nations in this group and ________ have been put into space．

1. A.
   dozen of satellite
2. B.
   two dozens of satellites
3. C.
   two dozen of satellites
4. D.
   dozens of satellites

 Today, there are more than 100 nations in this group and __________ have been put into

space.
  A. dozens of satellite                            B. two dozens of satellites 
  C. two dozen satellites                         D. two dozens satellites