The coal industry is the backbone of America.

 整个言语行为包括发声的行为和表达意义的行为。

It is better to be tried by twelve than to sit on the bench forever.

The best way to untangle a knotty tangle is not to “untie” the knots， but to keep pulling the loops apart wider and wider. Just make the mess as big， loose and open as possible. As you open up the knots they will unravel themselves. Works on cords， strings， hoses， yarns， or electronic cables.

数学之美在于它能够以精确而优雅的方式描述世界。

最可持续的森林是在保持其生态完整性的同时为人们提供价值的森林。