题目

    Mary is an American girl. She is now in Beijing with her parents. Mary doesn't know much Chinese, but she is studying it. She often speaks Chinese with her Chinese friends. Sometimes they can't understand her, because she can't speak Chinese very well.     It's Saturday morning. She goes out. She is walking in the street. She wants to go to the zoo to see the elephants and monkeys, but she doesn't know how to get there. She asks a Chinese boy the way. The boy can't understand her. Then she takes out a pen and a piece of paper. She draws an elephant on it, and shows the picture to the教室右面的墙壁长8米，高4米．墙上有2扇窗，每个窗的面积是5平方米．现在要粉刷这面墙壁，粉刷的面积是多少平方米？