在撞击过程中, 动量的变化是突然的,但非瞬时的.In a crash, momentum changes abruptly but not instantaneously.有时,在局部速度中可能出现瞬时脉动.Sometimes temporal fluctuation may take place inthe local velocity.它表示寻常光波前和非常光波前的瞬时轨迹.It represents the instantaneo...
I wish to furbish up the Russian I learnt at college.我要重温一下我在大学里学过的俄语.If you furbish up these old chairs, you'll have a better chance of selling them.你要是把这些旧椅子擦亮, 就会更好卖些.I wish to furbish up the French I learned at ...