( ) 5. — What are we supposed to do first if we want to develop our village? — Lots of new roads _____, I think. A. must built B. can build C. must be built D. can be built ( ) 8. Yang Liwei _____ about twenty-one hours in _____ around the earth fourteen times. A. took; going B. spent; going C. cost; to go D. took; to go 答案是C为什么不能选B B各项有什么区别