That which does not kill us makes us stronger.

但凡不能杀死你的，最终都会使你更强大。

Seemingly I have heard this from Linkon Park, and one of its members had committed suicide several weeks before.

It sounds a little ridiculous, the one who ever gave you strength and stimulation finally turned out to be a pessimist himself.

Maybe everyone has some diffcult times that others never know.

Maybe the thing is just that can kill him.

Now that we are still alive, we are still able to breathe, then we may not surrender to life or destiny.

The wisest mind has something yet to learn.

就连最智慧的人也有东西要学。

From George Santayana.

The following brief biography of George Santayana is from Wikipedia:

George Santayana, born on December 16 of 1863 and died on September 26 of 1952, was a philosopher, essayist, poet and novelist.

Orginally born in Spain, Mr. Santayana was raised and educated in the United States.

He studied in the Harvard University and finally became a professor of philosophy in Harvard.

Many of his students earned their own reputations, so he must be a good mentor.

Besides philosophy, Mr. Santayana also was a broad-ranging critic spanning many disciplines.

He should be considered as one of the wisest scholars in his field, but he wasn't statisfied with himself.

At the age of forty-eight, he resolutely left his position in Harvard and returned to Europe permanently, because at that time, Europe was the centre of technology and civilization in the world.

For everyone in the world, whether he is an expert or a mediocore, there are always numerous unknown things to him.

To keep pace with the world and not to be outdated, we must keep learning new knowldedge and new skills.

Besides, learning is not just reading or following other's example, it also involves summarizing one's own experience and creating new things.

But you have to figure out which ones are with greater importance and which ones are with fewer importance, so as to better allocate our limited time and energy.