: k0 O2 e' w+ g$ A: ^- z1 w* fTheory is when you know everything but nothing works. 4 ?1 G# q. t* [0 b1 a& m , V' ?# b' N4 APractice is everything works but no one knows why. ) P. P; M) ^$ j9 L' t( a9 t, G 5 e3 L# k- F9 M3 A$ Q' d, k这两天的情况是:Theory and practice are combined: nothing works and no one knows why.