Решение:
- I can / can't / might go out tonight. I'm't so busy.
- I haven't studied enough. I may / may not / might pass my exams.
- They say it must / need / might snow tomorrow.
- She can / must / won't be able to follow the law.
- Can / May / Might you come to my party?
Ответ: 1. can, 2. may not, 3. must, 4. must, 5. Might.