I must go.
I must to solve this task.
I must go to London.
He must be out.
We must build this house by autumn.
с отрицанием будет must not или mustn't
should not/shouldn’t
Should I play volleyball.
We should think about wild life more often.
He shouldn’t have exceeded the speed limit.
They left home 2 hours ago, so they should be here already.
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