Answer:
Simple sentence
I like spaghetti.
He reads many books.
She wrote.
She completed her literature review.
He organized his sources by theme.
They studied APA rules for many hours.
Compund sentence
She completed her literature review, and she created her reference list.
He organized his sources by theme; then, he updated his reference list.
They studied APA rules for many hours, but they realized there was still much to learn.
Complex sentence
Although she completed her literature review, she still needed to work on her methods section.
Because he organized his sources by theme, it was easier for his readers to follow.