A:Not at all.
B:Oh, it all depends.
C:It is all depending.
D:Yes, you are welcome
读“北美大陆沿40°N地形剖面图”,判断A山脉是:
图甲为一列简谐横波在某一时刻的波形图.a、b两质点的横坐标分别为x=2m和x=6m,图乙为质点b从该时刻开始计时的振动图象.下列说法正确的是( )
My sister always ____ one hour ____《Learn English》every evening.