I was ________ the point of telephoning him when his letter arri

I was ________ the point of telephoning him when his letter arrived.
A、to
B、on
C、at
D、in
【正确答案】：B
【题目解析】：on the point of doing sth. 是固定词组，意思是“正要、打算”。全句意思是“当他的信到的时侯，我正要打电话给他”。