The concept of legal obligation is central to the understanding of law.

解析：比喻立志用功需要循序渐进。

The most successful societies in the future will be those that are able to combine the strengths of both the state and the market.

"A book is a world you can hold in your hands."

释义：每个人应该先处理好自己的事情，不要去过多干涉别人的事情。