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The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.

Natural gas will play a critical role in the energy mix as we move toward a lower-carbon future.

有時候你必須做你必須做的事情才能生存。

The greatest happiness is to know the source of unhappiness.

沒有什么比只有一個想法更危險的了。