What can be shown, cannot be said.

If the job has been correctly done when a common stock is purchased, the time to sell it is—almost never.

水产养殖的创新必须在经济增长和环境管理之间取得平衡。

儿童心灵上的许多烙印，都是成人无意间烙下的。

夜晚最黑暗时，星星最明亮。