_ I was_______ the point of telephoning him when his letter arrive

_ I was_______ the point of telephoning him when his letter arrive

D

考查介词。on the point of doing sth.是固定搭配，另外注意这个句子中并列连词when连接的固定句型：on the point of doing...when...,意思是“正要干……这时……”，这样的句型还有 be about to do...when...,was doing...when...。