问题补充：
--- I really enjoyed talking with you ---but I’m afraid I must be off now!
---.
A. My pleasure
B. Nice to see you
C. Sorry to trouble you
D. So long
答案：
A. My pleasure
B. Nice to see you
C. Sorry to trouble you
(答案→)D. So long
解析：句意：--我真的很喜欢和你交谈，但是恐怕我现在要走了。--再见。My pleasure别客气；Nice to see you见到你很高兴；Sorry to trouble you打扰了；So long再见。根据句意故选D。
