The reason why a great conductor makes notations on his musical scores-marks them up again and again each time he returns to study them-is the reason why you should mark your books.

为什么一个伟大的指挥家会在乐谱上做记号——甚至每次研究都会重复标记——其中的奥妙正是你应该在书上做记号的原因。