下列语句中，描述天气的是（　　）

A．终年寒冷干燥

B．长夏无冬

C．晴空万里

D．四季分明

选择填空。

In class our teacher usually stands ______ the blackboard. [ ]

A．at the front of

B．in front of

C．at front of

D．in the front of