1．A familyfriendly ____________(气氛) in this hotel makes travelers comfortable.
2．It is reported that the talk will ____________(缓解) the tension.
3．The mystery of ____________(天文学) attracts many curious people.
4．They have almost spent as much as one ____________(十亿) dollars on this project.
5．An airliner ____________(失事) in west of Denver last night.
6．An astronaut will attempt to leave the stationary ____________(宇宙飞船) and then return to it.
