Answer:
A. I <u>must</u> leave immediately, as I have a bus to catch.
B. We <u>wouldn't</u> behave like the others.
C. It <u>may</u> rain in the evening.
D. You <u>can</u> exercise everyday.
Explanation:
Modal verbs are used to express ability, obligation, possibility, and so on. The modal verbs include can, must, may, might, will, would, should.