theory
The young man _______in studying paid no attention to the outside world.
Every possible means _______to prevent the air pollution, but the sky is still not clear.
The doctor had almost lost hope at one point, but the patient finally______.
All the neighbors admire this family_______ the parents are treating their child like a friend.
—Were you all frightened at the sound of the fire alarm?— No. Everyone stayed _______ and obeyed the police.