She brought with her three friends, none of__________ I had ever met before.
—What's that terrible noise?—The neighbors ________ for a party.
Every possible means ________ to prevent the air pollution,but the sky is still not very clear.
I invited Joe and Linda to dinner,but ________ of them came.
More and more people are willing to ________ part of their incomes to school children in the povertystricken areas.
Although he has not gone to college,he shouldn't ________ studying for his degrees.