$ J' J& H) j9 C( R8 X8 mTheory is when you know everything but nothing works.) |+ F3 K' E5 J+ A7 f
$ s4 j) N% x2 J$ c% sPractice is everything works but no one knows why. ) y* F$ n- Z2 l5 B1 ] 3 t/ R/ B: ? o6 o+ w2 {+ `: X这两天的情况是:Theory and practice are combined: nothing works and no one knows why.