This is our classroom. It's big and bright （明亮的） . There is a blackboard on the wall. It's a rectangle （长方形） . On the blackboard, there are two shapes ( 形状 ), one is a square ( 正方形 ), and the other is a circle ( 圆形 ). They're white. Beside the blackboard, there is a picture. It's a triangle ( 三角形 ). It's so beautiful. We like the picture very much. Above the blackboard, it's the National flag ( 国旗 ). It‘s a rectangle. It's red. It has a big star, and four little stars. The stars are yellow.