My elder brother my wet sports shoes and made me sit by the fire.
A:took off
B:kicked off
C:carried out
D:put out
下列哪些手术会明显影响动物的第二性征( )
You are____ (wave) to say goodbye.
质量为m1=1.0kg和m2的两个物体在光滑的水平面上正碰,碰撞时间极短,其位移随时间变化的x﹣t图象如图所示,则质量为m1的物体在碰撞过程中的动量变化量为____kg•m/s,m2的质量为____kg.