Today is Sunday. Jill and Tom are in the park. They see some grass under a big tree. It's green and soft. They want to sit under the tree. They put a towel(毛巾) on the grass. They sit on the towel. Jill feels something cold and hard. It's a stone(石头). Tom feels something soft, wet and thin. What is it? Wow, it's a snake(蛇)! They are afraid.
