You have to spend some energy and effort to see the beauty of math.
真正理解某件事的唯一方法就是自己去做。
Environmental stewardship is not optional - it's our responsibility to future generations.
The first erroneous assumption is that quality means goodness, or luxury, or shininess, or weight.
实现明天理想的唯一限制是我们今天的疑虑。