求助一道题 OG 10 49

pfullsomer

49.The cameras of the Voyager II spacecraft detected six small, previously unseenmoons circling Uranus, which doubles to twelve the number of satellites nowknown as orbiting the distant planet

(A)  whichdoubles to twelve the number of satellites now known as orbiting

(B)   doublingto twelve the number of satellites now known to orbit

(C)  which doubles to twelve the number of satellites now known in orbitaround
(D) doubling to twelve the number of satellites now known asorbiting
(E)   whichdoubles to twelve the number of satellites now known thatorbit


答案选择B
为什么不选择D
为什么 now known to orbit 比now known as orbiting好？

pfullsomer

be know to do, 没有be know doing的结构

pfullsomer

没看到那个as，当然to orbit好