Answer:
A way to rewrite the sentence using parallel structure is:
He was determined to pass the math course, not only to earn his three credits, but also to get a sense of achievement.
Explanation:
Parallelism consists of the repetition of a certain grammatical structure inside a sentence. The purpose of such repetition is to avoid confusion, making the speech clear, interesting, and easy to understand.
In the sentence, we use the structure "not only... but also..." The first part - the "not only" part - used a verb preceded by "to". However, the second part used the preposition "for" followed by a noun. Thus, we have two different structures. To make them parallel, we need to adjust one of them to be similar to the other. One way to do it is by using the "to + verb" employed int he first part for both:
- He was determined to pass the math course, not only to earn his three credits, but also to get a sense of achievement.
