Как образуется будущее веремя

21.I... remember her address.
A) can't B) should to C) ought
22.I was pushing the door with all might - but it... open!
A) shouldn't B) wouldn't C) hadn't
23. He sees very poorly. He... wear glasses all the time. A) has to B) ought C) can
24. The painting... be a masterpiece, but the colours are wonderful!
A) ought not B) may not C) must not
25.I will be worried, so you... phone me every evening.
A) must B) have C) should to
26. To save money you... take a sandwich to eat on the train. A) must to B) ought C) should
27. We're going to this performance! I... buy two tickets at a very ridiculous price!
A) might have B) was able to C) could to
28. It's Sunday tomorrow and we... to go to school.
A) mustn't B) shouldn't C) don't have
29. You've broken my cup. You... it!
A) needn't take B) didn't need to take C) needn't have taken
30. It's impossible! He... have taken the money!
A) was going to B) can't C) have to

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1) Что обозначает; 2) Как образуется; 3)Примеры.