—Listen！Helen is singing in the next room.—It be Helen .She has gone to Beijing.A. shouldB

问题补充：

—Listen！Helen is singing in the next room.

—It be Helen .She has gone to Beijing.

A. should

B. mustn’t

C. may

D. can’t

答案：

A. should

B. mustn’t

C. may

(答案→)D. can’t

解析：A. should 应该 B. mustn’t 禁止 C. may可能 D. can’t不可能；句意：听！海伦正在隔壁房间唱歌。不可能是海伦，她已经去北京了。故选D