【简答题】Passage A No very satisfactory account of the mechanism that caused the formation of the ocean basins has yet been given. The traditional view supposes that the upper mantle of the earth behaves as a ...
【单选题】词汇与结构 Flight time refers to "The total time from the moment an aircraft first moves under its own _____for the purpose of taking off until the moment it comes to rest at the end of the flight.