A、7 hours. B、14 hours. C、10 hours. D、8 hours. D本题考查的是时间计算的问题，图书馆从上午9点开到下午5点，一共应是8小时，故选D。

M: Here is your coat,
W: Thanks. It’ s very kind of you to invite us.
Q: What is the probable relationship between the two speakers?

W: When is the library open on Sunday?
M: From 9 a. m. to 5 p. m.
Q: How long is the library open on Sunday?