—Excuse me, where is Johnson?—He cannot go home, as his book is lying __________on his desk. 

John once worked in a remote mountain village school, which is ____only on foot. 

It isn’t quite ___ whether the Tibetan antelope is still being hunted.

It’s said that in the sea the fisherman caught a big fish ________.

It is not socially          for parents to leave children unattended at that age.