请教一道GMAT语法题~

题目

请教一道GMAT语法题~
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
为什么D不对?

答案

but的出现要注意平行,平行第一部分 The spraying of pesticides can be carefully planned,
平行的部分（but） accidents, *weather conditions that could not be foreseen,
平行的结构是n.+ can be done
A选项的错误在划线部分后面的---比较结构上,比较要注意语义明确 为避免歧义要补上比较对象和助动词 但是A选项they had中的they显然指代的是人 是人去anticipated
所以B是正解.
D选项 中的are not foreseeable显然未做到平行.
有人会说要用优先性来排除,确实有动词优于名词一说 但是这毕竟只是一个考察方面 .