☼ Could (do) and could have (done)
☼ Must and can't
☼ May and might (1)
☼ May and might (2)
☼ Must and have to
☼ Must mustn't needn't
☼ Should (1)
☼ Should (2)
☼ Had better It's time ...
☼ Can/Could/Would you ...? etc. (Requests, offers, permission and invitations)
