ПРОШУ ПОМОГИТЕ!!!Read these sentences and choose the correct answer to fill

ПРОШУ ПОМОГИТЕ!!!
Read these sentences and choose the correct answer to fill in the gaps.

That's the phone- who ____ it be?
must
can

You ____ enter the country without a visa.
must
can

My doctor says I ____ lose some weight.
must
can

Complete these sentences with 'can' or 'be able to'.

Ask him, he will __________ help you.
be able to
can

Don't shout, I _________ hear you very well.
be able to
can

If you try hard, you ______ pass your examinations.
are able to
can