In the United Nations Building, a group of interpretors are busily engaged in various international conferences. Besides their mother tongues, each oral interpretor must grasp at least two out of six UN formal languages. Usually, every UN conference lasts three hours. For conferences using Chinese and Arabic, three oral interpretors will be in place and twenty-minute interpretation assigned to each one in an hours. Since there are many countries speaking English, French or Spanish, when spokespersons speak any of the three languages, interpretors working in the same language may take a short break. But it is not the case for oral interpretors with Chinese or Arabic. When spokespersons use any of the four languages other than their mother tongues, oral interpretors need to translate the speech into Chinese or Arabic, or in the event that Chinese or Arabian representatives gives their speeches, interpretors should translate them into English or French. Therefore, they have to work through the three-hour conference without any break. As oral interpretors, their life is completely in the hand of those spokespersons. The speed, accent of spokespersons and difficulty of contents determine the quality of oral interpretion. If encountered with a fast-speaking one, interpretors may do it out of breath. When coming across those speakers with heavy accent, interpretors have to suffer from the working period. If, unfortunately, the spokesperson is of heavy accent, fast speaking, and delivers contents that hard to interprete, interpretors have to grind their teeth to make it anyway. No matter what kind of spokespersons, what contents they deliver and how they deliver, oral interpretors must try their utmost interpreting what they hear into their working languages. Sometimes, spokespersons speak in a very ambiguous way, interpretors cannot make decisions themselves to change it into a clear manner. Perhaps the objective of the unclear speech is not to make it understood by others, which is called "constructive ambiguity" in the diplomatical sense.