关于声现象,下列说法正确的是( )
A:人耳听觉频率范围是20Hz﹣2000Hz
B:女航天员王亚平在天宫一号上讲课的声音是通过声波传回地球的
C:运动员打鼓用的力越大,鼓声的响度就越大
D:“禁止鸣笛”是在传播过程中减弱噪声
食物中的营养物质主要有脂肪、糖类、蛋白质、水、____和维生素六大类.
Nobody knew who was the first ________ at school that morning when the window was broken.
Many ____ (visit) come to Kunming every year.