The government has taken measures air quality.
One-third of the country ________ covered with trees and the majority of the citizens ________ black people.
It is no good always complaining about life. ________ ,we are living.
By the time he was twelve, Edison __________ to make a living by himself.
As its name indicates, the “American Host Family” program gets American families __________in foreign students' lives in America and offers homes for them.
A lot of tall buildings __________ in Shanghai in the past three years.