题干
—May I speak to Mr. Smith?
— ，please．I'll see if he is in．
A：Look out
B：Hold the line
C：Keep up
D：Come on
答案(点此获取答案解析）
B
—May I speak to Mr. Smith?
— ，please．I'll see if he is in．
A：Look out
B：Hold the line
C：Keep up
D：Come on
