A:3或8
B:8或11
C:5或8
D:3或11
My daughter usually gets up at 6: 00 the morning, but Sunday morning she gels up at 8: 00.
一列简谐横波在t=0时刻的波形如图中的实线所示,t=0.04s时刻的波形如图中虚线所示.若该波的传播速度为2.5m/s,可判断( )
16÷2=____
24÷4=____