-- Sorry, it's already 6 o’clock. I have to be off for an appointment.
--- OK. .
A. It couldn’t be better
B. You really have me there
C. Let’s call it a day
D. Take your time
网友回答
A. It couldn’t be better
B. You really have me there
(答案→)C. Let’s call it a day
D. Take your time
解析：考查交际用语：A. It couldn’t be better再好不过了，B. You really have me there你把我难住了， C. Let’s call it a day是个固定短语，意思是今天到此为止的意思D. Take your time别着急，慢慢来，句意：--对不起，已经6点了，我得去赴约了。--好，今天就到这儿。选C。