— Listen! Someone is singing in the music room. It ______ be Jim. He practices singing there every day.

— It ______ be him. He has gone to Beijing. [ ]

A. can; can't

B. must; may not

C. must; can't

D. may; may not

病人突然呕吐出暗红色血块约1000ml，急诊胃镜示"食管静脉曲张破裂出血"，护士应估计病人目前最有可能先出现（）。

A.急性肾衰竭

B.心力衰竭

C.肝性脑病

D.感染

E.失血性休克