例句與造句

1. there are no other additive integrals of the motion . thus every closed system has seven such integrals : energy, three components of momentum, and three components of angular momentum
   這七個(gè)運(yùn)動(dòng)積分具有可加性固然不錯(cuò)，但為什么只有這七個(gè)呢？前面說積分常數(shù)就是運(yùn)動(dòng)積分（或許還包括它們的線性組合吧），而運(yùn)動(dòng)方程都是線性的，似乎那些運(yùn)動(dòng)積分都具有相加性??？
2. It's difficult to find component of momentum in a sentence. 用component of momentum造句挺難的