am is are 原形用在will be may be must be. 再答： might be . would be . can be . could be.to be. used to be.should be..... and you can put adjective or noun after the "be" to illustrate： 1.hey girl he loves u as soon as first see u ,can (could) u be his woman? 2.hey buddy u should be polite to everyone or somebody give you a course that how to be polite after clouting ur ass with stick until u charley horse