23. Of all the possible disasters that threaten American agriculture, the possibility of an adverse change in climate is maybe the more difficult for analysis.

(A) ....

(B) is probably the most difficult to analyze

(C) is maybe the most difficult for analysis.

这题目我倒是做对了，不难。但是，一直不明白它的解释里说的：Maybe must be replaced by probably.  我理解的是不是PROPABLY可以用在BE动词后面，而MAYBE要用在动词前面。

请大家指点

 不要想那么多

反正在GMAT语法里

maybe永远是错的,要改成probably

probably
源自拉丁词根prob 尝试；证明。可以证明地，因此变成大概地，很可能地。used to

say that something is likely to happen, likely to be true etc

maybe:
used to say that something may happen or may be true but you are not certain

也就是说，用probably基本上是“肯定”的含义。

而用maybe则是在“猜测、怀疑”。

Kaplan Gmat Grammer Reference解释：

Maybe: don't use "maybe" to modify an adjective or another adverb.

此题中的maybe相当于修饰了 the most..., "most"在此为adv（见AHD），它是不能被maybe

修饰的。