Ersatzverb (substitute form): to be able to
may – kann vielleicht, dürfen
might – kann vielleicht (schwächer als may)
might have – hätte können
After he had been allowed to drive that fast car, he won the race. (past perfect)
Ersatzverb (substitute form): to be allowed to
shall – sollte
should – soll
should have – hätte sollen
She was supposed to meet her instructor at the gym. (simple past)
In the 1980s the Millers emigrated to America where they were to stay for good. (simple past)
Ersatzverb (substitute form): to be (supposed) to (Wiedergabe einer Anweisung/vom Schicksal oder Umständen bestimmt)
ought to – soll
ought to have – hätte sollen
They ought to have helped the old woman carry her suitcases. (simple past)
kein Ersatzverb (no substitute form)
must – muss
They have to pack their bags for their trip to England. (simple present)
Ersatzverb (substitute form): to have to, to have got to
must not – nicht dürfen
They will not be allowed to travel if they can't display their passports. (conditional I)
Ersatzverb (substitute form): not to be allowed to