How can I say that something happens not for the first time?

Question

Would these examples be proper for written American English?

It happened not for the fist time that he decided not to attend classes.

or

It was not a single occasion/time when she decided not to attend classes.

Or any other suggestions? Thank you.

Answer 1

Both examples appear verbose and awkward though sentence structure and word choice always depend on what nuance you want to convey. The thought you seem to want to convey could be rendered for example by

Not for the first time, he decided to skip his classes.

or

He decided, again, not to attend his classes.

Answer 2

There are several possibilities, but the closest synthesis of the two sentences in the question (to use the original wording as much as possible) is this:

It was not a single occasion/time when she decided not to attend classes.
It happened not for the first time that he decided not to attend classes.

In short:

It was not the first time that he decided not to attend classes.

Other variations would involve actual rephrasing.