They were talking about the persons and things _______ they saw in the factory.
Many people are thinking of new ways to fight the pollution of the __________.
Mr. Brown had got a __________ and he went to see a dentist.
They didn't provide __________ for Mr. Brown, so he had to find a hotel to live in.
Some accidents have happened on the road recently. So we should pay attention to the __________ problems.
-Tom, do you know David Smith?-Sure. He is my best friend and our __________ has lasted for years.