【判断题】The chief purser is in charge of today‘s flight. (T or F )
【判断题】The chief purser has to check the documents. (T or F)
【单选题】During the briefing, the chief purser attendant assigns positions by _____ and qualifications.
【单选题】下列是美国《科学》杂志评出的2009年十大科学进展中的四项研究,主要属于化学探究领域的是 [ ]