The_______workcontinuedformorethanaweekbuttherewasstillnosignofthemissingboy.
Whenaspacecrafttravels,oneofthemajorproblemsisreentryintotheEarth’s_______.
Severalloudspeakersare_______fromtheceilingandwecanhearthespeakerveryclearly.
Theengineersinthislabspentseveralweeks_______theirplansforthenewbicycle.
Ifyouhaveanyproblemsduringyourstudyhere,pleasedonot_______tocallmeforhelp