this meaning is found in affirmative and negative sentences
is closely connected with the two above mentioned meanings
You must come and see us when you're in London
You mustn't cry
You must stop worrying about her son.
He must not leave his room for a while
This meaning is expressed in negative sentences
Is followed by the simple infinitive
Absence of necessity (не треба, немає необхідності) is expressed by other verbs
Obligation (from the speaker's point of view)
You must talk to your daughter about her future
Must he do it himself?
in this meaning only in affirmative and interrogative sentences
only the simple infinitive
Supposition implying strong probability
Напевно, повинно бути, probably
May be followed by different forms of infinitive
reference to the Present
The book is not on the shelf. Jane must be reading it.
Jane must read the book
He must be over fifty.
He must know all about it as he has read a lot on the subject
action in the past
Do you see him smoking over there? He must have finished his work.
indicates an action begun in the past and continued into the moment of speaking.
It must have been raining all the night. There are big pudles in the garden.
stative verbs - perfect infinitive is used
He must have been here since breakfast
He must have known it all along
may express an action going on at a given past moment
He must have been writing a letter when I came,
its use is restricted in two ways:
It is not used with reference to the future. In this case we find attitudinal adverbs in the sentence
He will probably come tomorrow
it is not used in the interrogative or negative form. It is found only in the affirmative form