It was from May 1 to Oct. 31,2010__________ the World Expo 2010 Shanghai was held,__________ was a great event for the Chinese people.
Now there are many _____ in our company.
We should think of ways to stop the waste from the factory _____ our living environment.
As far as I know, this man ____ risk anything than lose the ring for his wife.
She locked her room _____ a thief would break into it.
She said she would spend her holiday ___ Beijing.