---Did you have fun in the countryside yesterday?---Yes ._______,we felt cold and tired in the end.
Acid rain comes from _____.
Many _____ in ______ could hear no better than 65-year-old people, for they like pop music.
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.