以车为例，创建汽车接口，卡车和吊车均实现该接口。吊车可以吊起货物，卡车可以载货。在创建卡车和吊车对象时，输出“客车可以载货”、“吊车可以吊起货物”。-Take the car as an example, create the car interface, truck and crane to achieve the interface. The crane can lift goods, cargo trucks can. In the creation of trucks and cranes object, output　bus could carry ,　crane can lift goods .