GmatKiss wrote:Research during the past several decades on the nature of language and the processes of producing and understanding it have revealed not underlying simplicity but great complexity.

(A) of producing and understanding it have revealed not underlying simplicity but great complexity
(B) that produce and make it understandable has revealed great complexity instead of underlying simplicity
(C) by which it is produced and understood has revealed not underlying simplicity but great complexity
(D) by which it is produced and understood have revealed great complexity rather than underlying simplicity
(E) by which one produces and understands it have revealed great complexity instead of underlying simplicity

OA after sometime!

gunjan1208 wrote:I have a question:

"please clarify that object of the verb "produce" is missing here and also that the object can not be implied". I do not understand it and would like to know this rule. (Mundasingh123, Help!)

Thanks in Advance.

VivianKerr wrote:"Research" is the subject, and "have revealed" is the verb. Everything between them can be mentally deleted as extraneous.

Error #1 - Subject/Verb disagreement. We need the singular "has".

Eliminate A, D, and E.

Let's look at the differences between B and C:

B: processes THAT produce and make it understandable..._____ instead of ______.
C: processes BY WHICH IT IS produced and understood...not ______ but ______.

They are very close here. I don't see anything specifically idiomatically correct, but I would now choose B because it is more actively constructed.

Error #2: Active Voice/Passive Voice

"by which it is..." is just a more wordy and passive way to say "that".

IMO: B