21. — Would you like some more fried chicken?
— _____ It would make me gain weight.
A. Why not? B. Good idea. C. No, thanks. D. What for?
22. Studies show that _____ good health depends on _____ balanced diet and plenty of rest and exercise.
A. 不填; a B. the; a C. the; 不填 D. 不填; 不填
23. —Who______ it be that is knocking at the door?
—It ______ be Father, but I’m not sure.
A. can; must B. can; may C. must; can D. may; must
