A moment please. Im checking if Mrs. Brown free tomorrow.A. isB. beingC. to beD. will b

问题补充：

A moment, please. Im checking if Mrs. Brown free tomorrow.

A. is

B. being

C. to be

D. will be

答案：

A. is

B. being

C. to be

(答案→)D. will be

解析：根据时间状语tomorrow.可知答案为将来时，故选D