—Flight MU257 . I must be off now.—Have a nice trip.A. is being announcedB. has announc

问题补充：

—Flight MU257 . I must be off now.

—Have a nice trip.

A. is being announced

B. has announced

C. was announcing

D. had been announced

答案：

(答案→)A. is being announced

B. has announced

C. was announcing

D. had been announced

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