160. While some propose to combat widespread illegal copying of computer programs by attempting to change people's attitudes toward pirating, others by suggesting reducing software prices to decrease the incentive for pirating, and still others by calling for the prosecution of those who copy software illegally.

(A) by suggesting reducing software prices to decrease the incentive for pirating, and still others by calling

(B) by suggesting the reduction of software prices to decrease the incentive for pirating, and still others call

(C) suggest the reduction of software prices for decreasing the incentive for pirating, and still others call

(D) suggest the reduction of software prices to decrease the incentive for pirating, and still others by calling

(E) suggest reducing software prices to decrease the incentive for pirating, and still others are calling

Choice E, the best answer, uses constructions that are parallel to some propose', others suggest. . . , and still others are calling .... Choices A and B immediately lose the parallel construction, and also produce sentence fragments, by shifting to by suggesting ... and by calling .... Choice B starts like choice A and then shifts back to the verb call, losing the parallel with the second part (by suggesting). Choices C and D correctly begin the second part of the parallel by using suggest. Choice C, however, introduces the nonidiomatic for decreasing, which creates some difficulty in meaning. Choice D loses parallel construction in the third part by shifting to by calling.

How about answer A, in which similar part "propose to combat widespread illegal copying of computer programs " are omitted and uses parallel structure by...by... and by...?

问得好，问得妙！

是不是需要用do so 在两个by之前？

总觉得E也不是那么对称