如下图所示，观察四个几何体，其中判断正确的是(　　)

​任务型阅读

    John had a busy weekend. On Saturday morning, he went to the library and studied math. On Saturday afternoon, he went to the park. He played tennis with his friend. Lisa was busy on Saturday, too. She cleaned her room in the morning. In the afternoon, she wrote a letter to her cousin(表妹).

    On Sunday morning, John and Lisa read books at home. On Sunday afternoon, they practiced English. In the evening, they saw an interesting talk show with their parents. They had great fun.

若一个多边形的每一个外角都等于40°，则这个多边形的边数是（　　）

﹣27的立方根是（　　）