Ответ:

You must study for the exam if you want to pass.

We should take a break and relax for a while.

They can't attend the meeting tomorrow due to a prior commitment.

I might go to the concert tonight if I can get tickets.

She could help you with your project if you ask her nicely.

We ought to arrive at the airport early to avoid any delays.

He shouldn't eat too much junk food if he wants to stay healthy.