Here are the best choices for each sentence:

6. She'd rather **c) to work** than go to university.
7. I'd rather you **a) work** than went to university.
8. I'd rather **d) to live** alone than lived with him.
9. I'd rather you **b) live** alone. It was a mistake.
10. It's time we **d) finished** this exercise.

So the completed sentences would be:

6. She'd rather to work than go to university.
7. I'd rather you work than went to university.
8. I'd rather to live alone than lived with him.
9. I'd rather you live alone. It was a mistake.
10. It's time we finished this exercise.