成功无法保证，并非唾手可得。成功必须靠自己去争取。Success is not guaranteed. It is not handed to you. Success is earned.他懊悔地坐在靠窗的椅子上。He sat penitently in his chair by the window.他靠每周领取的作为病残养老金的直接转账救济支票过日子。He lived on an invalidity pension which ...
However, momentum is always conserved in a collision, whether or not the collision is elastic.然而, 不管碰撞是不是弹性的, 在碰撞过程中动量总是守恒的.The elastic interaction between a wedge disclination dipole and an interfacial crack was investi...