交换力的条件与同位旋完全无关.The condition of an exchange force has nothing to do with isospin.同位旋是矢量.Isospin is a vector quantity.由激光发射出的光线都是同位的.All rays leaving the laster are in phase....
He sounded so posh on the phone.在电话里听起来，他的谈吐非常优雅。She always puts on a posh voice to talk to the vicar.她总是装腔作势,用一种优雅的嗓音跟教区牧师讲话.Now he's got a posh car, he thinks he's arrived.现在有了豪华汽车, 他想他已经功成名就了....