The best way to learn mathematics is to do mathematics.

解释：高明的医生注重预防疾病，而不是等到疾病发生后再去治疗。

如果你不相信爱，那么生活的意义是什么？

我喜欢挑战自己，把自己推到极限。

最好的交易者是那些能够适应不断变化的市场条件的人。

找到我，我会和你一起生活。

外国势力似乎并不理解我们政府的真正特性。

We've done price elasticity studies, and the answer is always that we should raise prices. We don't do that, because we believe -- and we have to take this as an article of faith -- that by keeping our prices very, very low, we earn trust with customers over time, and that that actually does maximize free cash flow over the long term.