.I __________ be afraid to sleep alone in my room, but now I _________ sleeping there alone.
Mr. and Mrs. Green work in the hospital, but they have no children. So they belong to _____.
_____ is a program to help children’s education in poor areas.
About _____ of the world population is Chinese.
We should plant more trees on sides of the street.
your help, we can finish the task in time.