问题补充:
—The old man is ill. He to the hospital at once.
--Don’t worry. A doctor to come already.
A. must be sent , has asked
B. must send, have asked
C. must be sent, has been asked
D. must send, have been asked
答案:
A. must be sent , has asked
B. must send, have asked
(答案→)C. must be sent, has been asked
D. must send, have been asked
解析:句意:---这个老人生病了他必须马上被送到医院,----不要担心,医生已经被叫来了。 Must be done 表示含情态动词的被动语态,完成时的被动语态have been done 结构,根据题意可知选C