As we all know it is usually cold in this place in January but it be warm sometimes.A.

问题补充：

As we all know, it is usually cold in this place in January, but it be warm sometimes.

A. must

B. can

C. should

D. would

答案：

A. must

(答案→)B. can

C. should

D. would

解析：考查情态动词辨析。A必须，一定；B可能，能够；C应该；D会；句意：据我所知，这个地方的一月份通常比较寒冷，但是有时候也可能比较温暖。根据句意说明B正确。