6. He had thousands of students, many of ______ gained great success in their own field.
-The cars give off a great deal of waste gas in the street.-Yes, but I'm sure something will be done to __________ air pollution.
__________ either you or I to look after her?
The lion is considered king of the forest as it is a(n)__________ of courage and power.
Our enlarged school campus is __________ the old one.
Many of the scientists and engineers are judged __________ how great their achievements are.