Situation: Two persons are talking on the campus.
Speaker A: Excuse me. Is the library open all day?
Speaker B: _________. Only from 8 a.m. to 4 p.m.
选择一项：
a. That.s right
b. Sorry, I.m afraid not 解析：交际用语。由后句“只是从上午8点到下午4点”，前句意为“对不起，我恐怕不是的”，因此选D。
c. Sorry, I.m not sure
d. Yes, of course