而是；更确切地说；还不如说；相反 You use rather when you are correcting something that you have just said,especially when you are describing a particular situation after saying what it is not.
Twenty million years ago,Idaho was not the arid place it is now.Rather,it was warm and damp,populated by dense primordial forest...
2,000万年前,爱达荷州并不像现在这样干旱.相反,那时的爱达荷州温暖潮湿,有大片的原始森林.
But there must be no talk of final victory; rather,the long,hard slog to a solution...
但是这还谈不上是最后的胜利；而是长期、艰难地寻找解决方法的过程.