When you solve a mathematical problem, you don't just get the answer - you understand why it's the answer.
大陆漂移的第一个概念早在1910年就浮现在我的脑海中,当时我在观察世界地图时,受到大西洋两岸海岸线吻合的直接印象的启发。
If you're not failing occasionally, you're not pushing the boundaries enough.
当年的年轻人已变成了花下之尘。