It _________ be the only way to solve the problem. There are other choices.
may not
mustn’t
need
should
It ______ Mr. Smith half an hour _____ get to his office.
Mary, ______ girl, wants to be a doctor.
Our teacher always helps us ______ our English.
--- _____ do you ______the book? --- It’s very interesting.
Trees are animals’ homes, so we shouldn’t ________.