. — Flight 551 for Dalas . I must be off now. — Have a pleasant trip then.A. is being anno

问题补充：

. — Flight 551 for Dalas . I must be off now.

— Have a pleasant trip then.

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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