The pursuit of science is not a luxury but a necessity for the survival of mankind.

译文：有钱人家习惯了奢侈无度，教导子弟却成了难事；贫穷人家要谋生计，还是要靠读书获得出路。赏析：衣食无忧的家庭虽然能给孩子提供良好的物质条件，但也最容易让孩子养成穷奢极侈的作风。读书也许不是人生唯一的出路，但却是普通人最好走的那条路，这条路成本最低。

"Courage is not the absence of fear, but the triumph over it."

I never stop learning and improving.

The highest endeavor of the mind， and the highest virtue， is to understand things by intuition.

要信守承诺。