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mission – n. a flight by an aircraft or spacecraft to perform a specific task
era – n. a period of time that is associated with a particular quality, event, person, etc.
on board – prep. phrase in or on a train, boat, etc.
tour – n. an activity in which you go through a place (such as a building or city) in order to see and learn about the different parts of it
doll – n. a child's toy in the form of a baby or small person
rotation – n. the act of regularly changing something by replacing it with something else
