-----Mr. Smith can I come to ask for some advice on my paper at any time?---Yes of co

问题补充：

-----Mr. Smith, can I come to ask for some advice on my paper at any time?

-----Yes, of course. .

A. If you’re convenient

B. At your convenience

C. That’s right

D. Don’t mention it

答案：

A. If you’re convenient

(答案→)B. At your convenience

C. That’s right

D. Don’t mention it

解析：考查交际用语的使用。 At your convenient在你方便的时候。A项表达错误，convenient主语不可能是人。根据语境，B项正确。