What is the most important way for people to use more fresh water according to the author?
A．To take more water from the sea.
B．To protect mountainous areas.
C．To save more water in daily life.
D．To protect the natural ecology balance.

单项选择题Speaker A: I have two tickets for the concert tonight. Would you like to come? Speaker B: ______A．I'd love to, but I promised my mother I'd take my sister to a show.B．Really? When did you buy the tickets?C．Why do you ask me to go with you?D．I can't because actually I'm not very keen on concerts.

单项选择题Speaker A: Do you mind if I open the window? Speaker B: ______A．Yes, please open the window.B．Yes, I do find it is very stuffy in the room.C．No, I don't. Don't open the window please.D．As a matter of fact, I'm feeling a bit chilly.