Sure! Here’s a rewritten version of the sentences:

1. You must fill out this form to participate in the contest.
2. Your brother might get tired tomorrow if he stays up late tonight.
3. If it rains tomorrow, we may have to delay the meeting.
4. You can finish your test and leave for home immediately.
5. Linda might have enough money to travel to Europe if she wins the contest.
6. You should dress appropriately and behave politely at the formal event.
7. They must win the competition if they want to give their best performance.