When you are speaking on the phone, you must convey the impression that this is an important conversation to you, you are treating with great significance.
A. one
B. the one
C. that
D. it
网友回答
(答案→)A. one
B. the one
C. that
D. it
解析：考查代词。句中one代指前面的an important conversation，属于泛指，后省略关系词that。句意：当你在电话通话的时候，你必须传达这是一个非常重要的谈话这样的印象，一个你正在高度重视的谈话。故A正确。