There are my legs(这是我的腿). I walk and run with my legs(我用腿走路和跑步) is a thigh(这是大腿)Thigh is the upper part of the leg(大腿是腿的上部)，which connects the hip and the knee(连接臀部和膝盖)This is my calf(这是我的小腿肚)，calf is the back portion of the lower leg(小腿部是小腿的后部).
