John plays football _______, if not better than, David.
All flights ____ because of the snowstorm, many passengers could do nothing but take the train.
As he works in a remote area, he visits his parents only ____.
It was the training ____ he had as a young man ____ made him such a good engineer.
Nobody but doctors or nurses and those____ by Dr.Hu ____ to enter the patient’s room.
The owner of the shop asked his assistant to ____ the pears that can be thrown away.