He has come to be recognized as an expert in the problem of overpopulation and food supply.
由于他的经验促使他终于成为了公认的人口过剩和食物供应问题的专家。
People who work in offices are frequently referred to as white-collar workers' for the simple reason that they usually wear a collar and tie to go to work.
坐办公室的之所以常常被称作“白领工人”,就是因为他们通常是穿着硬领白衬衫,系着领带去上班。