— After the 2008 Olympic Games, more and more people in western countries begin to learn Chinese _____

     they can better understand the culture of China.     

— I'm sure they will. [ ]

A. because of

B. even though

C. so that

D. as if

长征三号火箭运载同步卫星升空，当卫星脱离火箭绕地球运转时，以______为参照物，卫星是静止的．