---Susan, why are you still here? They are all ready to start. ---I’m sorry, but I _____when to meet.
Hiking is ________ in spring, I think.
If you have ______ try, I’m sure you’ll get the right answer.
Who taught ______ history last term?
Many people watched the opening ceremony of the 2013 Shanghai Tourism Festival ______ September 14.
I would like to play piano instead of playing ____ chess.