—David, how old is your father this year?
—      . And we just had a special party for his       birthday last weekend.

It’s reported that there are more than 300           smokers in China, nearly a third of all the smokers in the world.

—“Food Safety” has become one of the hottest topics recently.
—Yeah, it receives         Internet hits(点击) a day.

There are over         trees in my school, so the air is very fresh.