The best time to plant a tree was 20 years ago. The second best time is now.
任何实验的价值和效用都取决于材料是否适合其使用的目的。
I don't believe in heroes, but I believe in people who do heroic things.
千里之行,始于足下,再近的道路,如果你不走,就永远不能到达;一屋不扫,何以扫天下?再小的事情,你都不去做,何谈成功?