世贸组织是世界上最大的多边贸易组织,它为国际贸易制定了一系列基本原则和协定,其最重要的原则是[ ]
A、市场准入原则
B、互惠原则
C、非歧视原则
D、公平竞争和公平贸易原则
答案:C
— Have you finished your homework yet?
— Not yet. I only ___ to do it just a few minutes ago. [ ]
A. got down
B. set out
C. set about
D. set up
工程车辆制动系应如何进行调整?