21. — Oh. dear! I wish I had not taken ________ lift.
— If I had known it would be out of ________order, I would have stepped up.
A. the; an B. a; the
C. a; 不填 D. the; 不填
22. — Is Catherine seriously ill?
— ________ . She is in hospital and remains unconscious （昏迷不醒）.
A. I don’t think so B. I’m not sure
C. I'm afraid so D. I hope not
23. — Excuse me, ________ Mr White ________office work this week?
— No. He is on holiday.
A. has; done B. did; do
C. does; do D. is; doing
