.--Your parents were anxious about you. You _____ home without saying a word.
-- It’s my fault.

Sir, you ________ take this seat. It’s just for the old.

— Look, it _____ be Jack who is at the gate of the library.
It _____ be him. He has gone abroad.
may; must   B. must; mayn’t C. must; can’t    D. can; mayn’t

— My dog is really fat.   — You______ have given it so much food.

Please remind your grandpa to take medicine on time, for a man of his age ____be very forgetful．

— Mary looks hot and dry.
— So ________ you if you had a high fever.

—Why didn’t Sam attend the party yesterday evening?
—He ___ not have wanted to see me.

The World Wide Web is sometimes jokingly called the World Wide Wait because it _______ be very slow.

Please remind me in case I ______ forget.