A proof tells us where to concentrate our doubts.

我认为，为了看学生是否符合教师设定的某些标准而测试其成绩，与治疗对有意义学习的启示直接相悖。

I think it matters whether someone has a good heart.

The end of history will be a very sad time. The struggle for recognition, the willingness to risk one's life for a purely abstract goal, the worldwide ideological struggle that called forth daring, courage, imagination, and idealism, will be replaced by economic calculation, the endless solving of technical problems, environmental concerns, and the satisfaction of sophisticated consumer demands.

一个有趣的事实是，岩石越古老，与今天的岩石差异越大。