Eye doctors recommend that a child's first eye exam ________ at the age of six months old.
How close parents are to their children ________ a strong influence on the development of the children's characters.
As a result of the destruction of the forest, a large ________ of animals ________ lost their living places.
One third of the country________covered with trees and the majority of the citizens________black people.
________of the land in that district________covered with trees and grass.
________of the people on the Net ________China's economy is among the strongest in the world.