He is in _______.

—You look so worried, what’s wrong?—More and more people like me become to worry about the __________ pollution  after the haze (雾霾) appeared in Beijing and some other cities in China.

 Does Simon have two ________ of ________ ? 

We don’t sweep the floor for a few_________ .     

 –What do you think of the summer camp?–Wonderful! It’s the greatest ______ I have ever had.