All the neighbours admire this family ____ parents are treating their child like a friend.
I was about to leave __________ someone knocked at the door.
I __________ what he said and I __________ him.
—I wonder why Tom left without a word. —He __________ have had some trouble, for he looked dull.
I had just got up and was about to cook my breakfast__________ the telephone rang, but it was hung up __________ I could answer it.
Swimmers must be very strong in order to build up speed because of the high resistance (阻力)of the water. Runners,__________, must struggle against the heavy resistance of the air and ground.