关于这道请问有解释吗

hukai901

T-9-Q41. 987-830

The spraying of pesticides can be carefully planned, but accidents, weather conditions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had anticipated.
A.    weather conditions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had
B.    weather conditions that cannot be foreseen, and pilot errors often cause much larger deposits of spray than
C.    unforeseeable weather conditions, and pilot errors are the cause of much larger deposits of spray than they had
D.    weather conditions that are not foreseeable, and pilot errors often cause much larger deposits of spray than
E.    unforeseeable weather conditions, and pilot errors often cause much larger deposits of spray than they had

毛毛carina

提供两个讨论帖：

http://forum.chasedream.com/GMAT_SC/thread-536342-1-2.html

http://forum.chasedream.com/GMAT_SC/thread-463750-1-2.html