你送给我桃子,我就回报给你李子。意思是做人要知恩图报,不能忘恩负义。也比喻礼尚往来,相互赠送礼物。
The past is already written. The ink is dry.
应对不自由世界的唯一方法是变得如此绝对自由,以至于你的存在本身就是一种反抗。
The concept of NP-completeness has provided a powerful tool for understanding the complexity of computational problems.