Whenaspacecrafttravels,oneofthemajorproblemsisreentryintotheEarth’s_______.
A、surfaceWiththehelpofthegovernment,alargenumberofpeople---_______afterthefloodin1991.
Wecannottrusthimanymorebecauseheoften________hisduty.
Heworksinouruniversityasavisiting_______,notasaformalfacultymember.
The_______workcontinuedformorethanaweekbuttherewasstillnosignofthemissingboy.
Carelessnessmadehimfallinhisjob_______.
