题目

Welcome to Green Water School, everyone! Today is your first day in our school. I will tell you our school rules. All of you should know them.First, every student has to wear a uniform at school. Students should wear sports shoes for P.E. class and should not wear hats in class. Second, students have to have lunch in the dining hall. Anyone can’t eat in the classroom or outside. Third students should clean the classrooms after every afternoon. And before leaving the classrooms, you should make sure the lights are off.That’s all. I hope you have a happy time in Green Water School!根据短如图所示，小刚在艺术节上用吉他弹奏优美的乐曲．对于吉他发出的声音，下列说法正确的是（ ）A．乐曲的声音是通过空气传入人耳的B．变换手指按压弦的位置可以改变声音的响度C．用力拨动吉他弦可以提高声音的音调D．拨动不同的吉他弦可以改变吉他的音色