粤菜、川菜、湘菜是我国著名的菜系，其发源地分别是（　　）

七巧板被西方人称为“东方魔板”．如图的两幅图是由同一副七巧板拼成的．已知七巧板拼成的正方形的边长为8cm，则“一帆风顺”图中阴影部分的面积为（　　）

    Do teenagers in small villages do chores at home? How about the teenagers in big cities? Here is a survey. We asked 4,000 teenagers in China several questions. Half of them come from big cities like Beijing, Shanghai and Guangzhou. The others are from small villages. We made a diagram of the result of our survey. Let's have a look at it. We found out that teenagers from small villages do more chores than those from big cities. Maybe it is because they live a harder life. Our advice to parents in big cities is that parents should give their children some chores to do. Doing chores teaches teenagers to take care of themselves.

    Chores 2000 teenagers in small villages.

    Chores 2000 teenagers in big cities

草原面积广阔的地区主要分布在（  ）