A:大光圈、平面镜
B:大光圈、凹面镜
C:小光圈、平面镜
D:小光圈、凹面镜
在三个大洲的轮廓图中,加点地区的气候特点为( )
下图所示省级行政区,位于我国地势第三级阶梯的是 ( )
—Mr. Smith, Can you give us some advice on how to learn English well'?
—Remember, Nothing can be learned well ______hard work.