In the face of all these difficulties, we're not discouraged and keep ________ good spirits.
They prepared manmade rubber as a substitute________ the natural rubber that they could no longer obtain.
After years abroad, he returned to his hometown, ________ he spent his childhood.
The governor is occupied ________ the meeting at the moment. May I take a message?
It's dark and little Anne can't find her way home. She really doesn't know what ________(do)．
Doctors strongly recommended that my father ________(take) more exercise regularly instead of sitting still before a computer all day long.
