题目

I have a friend. She doesn’t walk, talk or laugh, but she is very kind and friendly to me. When I feel tired, she can help me ______. She makes me happy almost every day. You can’t touch or see her, but she’s ______. Do you know who she is? She is my best friend — music.Music is my favorite type of art. When I was four years old, I began to listen to different kinds of music. The first time I saw a piano, a black-and-white musical instrument, I was attracted by it.At first, I was ______ playing the piano. But, as a four-year-old girl, classical music is not very attractive to me. So, I反比例函数y=（k≠0）的图象上有一点P（m，n），且m，n是一元二次方程x2-4x+3=0的两根，则k=（    ）A.4B.-4C.3D.-3