改变令人不适，但它是进步的必要条件。

The downside of my celebrity is that I cannot go anywhere in the world without being recognised. It is not enough for me to wear dark sunglasses and a wig. The wheelchair gives me away.

Sustainability is not an option; it's a responsibility we owe to future generations.

A proof of a proposition is a process the nature of which is such as to produce in us a belief in that proposition.