Careful management of a development project can not only ...

[doclkk]

Careful management of a development project can not only prevent much laborious debugging along the way but also can avoid painful specification changing

B. and also prevent the changes in specification that can prove so painful
C. Or also avoid painfully changing specifications
D. but also can stave off painful changes in specification
E. but also stave off painful specification changes

My guess was D

Veritas Answer E

Can someone explain why it is that? [/spoiler][/u]

[tdadic84]

IMO E...

"Not only X...but also Y"

Here...the X = prevent...therefore the Y must = stave....

in D...the X = prevent and the Y = can stave...

this is not the correct idiom...must be written the sme way

[dendude]

The idiom construct is Not only X but also Y
So E fits the bill.
D on the other hand repeats the word can in the "but also" segment of the idiom.

If the sentence was - Not only can prevent....
then D would probably be right, since can was included in the "Not" segment and would also need to be included in the "but also" segment.
Since can was used before the idiom construct it does not need to be repeated. It is understood.

Hope this makes sense.