The only limit to our realization of tomorrow is our doubts of today.
Every man has his secret sorrows which the world knows not; and often times we call a man cold when he is only sad.
世界是一首伟大的歌，我们是其中的歌手。
The best scientists are those who never stop asking why.
The conversation about coal must move beyond 'pro' or 'anti'—we need solutions, not slogans.
The true measure of success is how much we can give back to the communities that support our business.