We _______ on this project for four hours. Let’s have a rest.
The soldiers were fighting bravely their people _____ the invaders.
Two dogs_____ a bone, and a third one ran away with it.
Though he failed in the exam this time, he did not.
Mrs. Brown went to the doctor’s because she had some trouble_____ her heart.
The teacher as well as the students when I came into the room.