The following sentence illustrate several kinds of nonparallel constuction. Rewrite the sentence to achieve parallelism.

If you insist on reading the Old Testament all the way through and to do the same with the New Testament, you are in for some big surprises.

Would you write it like: If you insist on reading the Old Testament all the way through and doing the same with the New Testament, you are in for some big surpises.
or..........
If you insist on reading the Old and New Testaments all the way through, you are in for some big surprises.

But if I wrote it using the second approach would that be showing parallelism. that is my only concern with that sentence.

Your first revision seems to have parallel structure in it, but it's terribly wordy -- redundant -- not good.

The second revision is parallel and concise.

You must choose, though. You must use the one that will fulfill the assignment your teacher gave you.

=)

The second revision, "If you insist on reading the Old and New Testaments all the way through, you are in for some big surprises," does indeed demonstrate parallelism. It maintains consistency by using the same structure for both phrases: "reading the Old and New Testaments all the way through." This parallel structure helps to improve the clarity and effectiveness of the sentence.