One day, little Roy was ill. So his mother took him to the clinic( 诊所 ). A doctor examined him and said : “ Well, boy, there is something wrong with you. I am afraid you need to get injections ( 输液 ) twice a day 。 Then you will feel better soon. A nurse will give you the injection later. Roy thought it would hurt so he was afraid。 His mother wanted to comfort him. "Sweetie. don't be nervous. I'm here. If you're brave, I'll take you to the zoo on weekends. I promise ! ” “ Great! Mum, I love animals!" said R oy. Just then a young nurse came and said to him with a smile,"I am going to give you the injection now, Roy , Where do you want it? Left arm or right arm? ” But Roy got scared again. He thought for a while and asked, “ Nobody has let me choose that before. Must I choose now?” “ Yes,Roy," the nurse replied,“ Where do you want it? “Well, Roy answered in a low voice,“ I want it in your left arm, please