can和potentially到底是否redundant?

找到两个例子,一个可以用,一个不可以用

先是OG

159. While depressed property values can hurt some large investors, they are potentially devastating for home-owners, whose equity—in many cases representing a life’s savings—can plunge or even disappear.

(A) they are potentially devastating for homeowners, whose

(B) they can potentially devastate homeowners in that their

(C) for homeowners they are potentially devastating, because their

(D) for homeowners, it is potentially devastating in that their（A）

(E) it can potentially devastate homeowners, whose

Choice A is the best. Its wording is unambiguous and economical. The plural pronoun they agrees with its antecedent, property values. The pronoun whose clearly refers to homeowners and efficiently connects them with the idea of lost equity. In B, C, and D, substituting in that their or because their for whose is wordy and confusing since the antecedent of their might be they, not homeowners. Furthermore, can potentially is redundant in B and E. Both D and E use the singular pronoun it, which does not agree with its logical antecedent, property values.

再来大全的

212. Following the destruction of the space shuttle Challenger, investigators concluded that many key people employed by the National Aeronautics and Space Administration and its contractors work an excessive amount of overtime that has the potential of causing errors in judgment.

(A) overtime that has the potential of causing

(B) overtime that has the potential to cause

(C) overtime that potentially can cause

(D) overtime, a practice that has the potential for causing（E）

(E) overtime, a practice that can, potentially, cause

怎么这里又可以用了?

在OG那题中，potentially和can同时指向devastate，所以redundant，你只要用一个就可以了，要么can devastate，要么potentially devastate。

在大全那题中，potentially修饰can，can指向cause。意思是很有可能（potentially）可以（can）造成（cause）。。。

所以说永远不要去死记硬背考点，做语法题要从理解句意出发，要做到手中无剑，剑在心中，无招胜有招。：）：）

可以参考: http://forum.chasedream.com/dispbbs.asp?BoardID=23&replyID=564638&id=14418&skin=0

携隐mm高见！最后达到人剑合一，就是native speaker的境界！