VOA慢速英语:Secret Space Plane Lands After Two Years in Orbit

alarm clock - n. a clock that can be set to sound an alarm at any desired time

garage - n. a building or part of a building in which a car, truck, etc., is kept

mission – n. a flight by an aircraft or spacecraft to perform a specific task

orbit - v. to travel around (something, such as a planet or moon) in a curved path : to make an orbit around (something)

classified - adj. kept secret from all but a few people in the government