The balance between economy and ecology is the core of modern forestry.

文学是人类的记忆。

我不需要理由去相信自己。

The concept of reducibility is central to understanding the relationships between different computational problems.

Imagination is the beginning of creation. You imagine what you desire, you will what you imagine, and at last, you create what you will.

你和我各有一个苹果，如果我们交换苹果的话，我们还是只有一个苹果。但当你和我各有一个想法，我们交换想法的话，我们就都有两个想法了。