his is our classroom. It's big and bright （明亮的） . There is a blackboard on the wall. It's a rectangle. On the blackboard, there are two shapes, one is a square, the other is a circle. They're white. Beside the blackboard, there is a picture. It's a triangle. 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.