我们对未来持乐观态度，但我们知道仅靠乐观是不够的。

The writer must believe that what he is doing is the most important thing in the world. And he must hold to this illusion even when he knows it is not true.

DJI's success comes from our persistence in technology.

学习新编程语言的最好方法是用它编写程序。