我能把句子补充完整，并加上标点。

(1)北京的夜晚                                         

(2)丑小鸭                                              

(3)日月潭                                               

(4)北斗七星像                                             

(5)小鸟                                               

It ___ be the postman at the door. It’s only six o’clock.

A．mustn’t

B．can’t

C．won’t

D．needn’t