You will ... speak English better if you communicate with Englishmen more often.
can
have
be able to
ought

I want ... speak English fluently.
to can
to be able to
to have to
could

I ... get up early not to be late for my lesson.
am able
have to
must
may

I ... have called you before coming.
should to
ought to
had to
could

Small children ... obey their parents.
ought to
need to
must
may

Nobody answers the phone. They ... be away.
should
would
can
must

You ... worry about your examination because you are well prepared for it.
need not
need not to
could not
must not

... you, please, close the door?
will
should
could
would

You ... not smoke here.
may
have to
must
ought to

You ... consult the dictionary to translate this word.
should
must
can
have to

... I speak to Mr.Collins, please?
could
shall
must
ought

You ... take so many heavy books to school with you.
need not
must not
ought not
should not

You ... take care of your health!
may
ought to
must
should

The passengers ... come in time not to miss the plane.
should
must
might
need not