There were about six ______ students in the school building during the earthquake, and ______ of them didn’t run out.
According to the new family planning policy in China, a couple can have a_______child if one of them is an only child. A. two B. second C. twice
Look at the sign _______! We shouldn't park our car here.
The telephone rang_______ Jenny was practicing the violin. A. until B. before C. while
--- Hi, David. _______do you go to see your grandparents? ---About three times a month. A. How long B. How often C. How soon
The year of 2013 saw the_______ air pollution in China for 52 years. A. bad B. worse C. worst