数学的本质在于其自由性。

相信生活，它给人的教益比任何一本书籍都好。

We must balance the need for energy security with the imperative of reducing emissions.

漂亮的女人休要让她老去，风流浪的子不要让他贫困。

The task of the leader is to get his people from where they are to where they have not been.