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。
We must focus on customers and continuously improve the quality of products and services.
弦理论的景观是广阔而复杂的,可能有10^500个不同的可能宇宙。