单项选择题
Prices may change quickly if supply or demand（）.
A. changes B. change C. will change
单项选择题 A:Hi Bob, Id like to congratulate you on the progress of Beihai project. B:（）
单项选择题 A:Oh. But why didnt he just own up and tell someone? B:（）
单项选择题 A:Here you are, Sir. B:（）
