概念二L85,Mr.Page will have been teaching for a total of forty years!这个时态是将来完成进行时吗

概念二L85,Mr.Page will have been teaching for a total of forty years!这个时态是将来完成进行时吗 will be 什么时态例如Mr.Reginald Page ,will be retiring next week. Mr.Page will have been teaching for a total of forth years.在这句话中,我想知道为什么要用will have been teaching(will have been doing)这个时态,而不是will have teached(have been done) 非谓语形式的用法I have just received a letter from my old school,informing me that my former headmaster,Mr.Stuart Page,will be retiring next week.我想把informing me that 换成是 informed that my former headmaster,Mr.Stuart Page,will be r page page. 请问这句话的informing me that my former headmaster怎么理解做什么成分I have just received a letter from my old school,informing me that my former headmaster ,Mr Stuart Page ,will be retiring next week. 请帮我分析一下下面句子中informing这个分词是作什么句子成分,I have just received a letter from my old school,informing me that my former headmaster,Mr Strart Page,will be retiring next week. Mr.Li,he will forgive you will find the story at an eighth page 翻译 I received a letter from my old school .It tells me that my former headmaster ,Mr Stuart Page ,will retire next week .Pupils of the school ,old and new ,will send him a present to say good-bye .We will prepare a large album .All those who join in sen 二所有概念整理. 二所有概念整理 新概念英语解析.I have just received a letter from my old school,informing me that my former headmaster,Mr.Stuart Page,will be retiring next week.Pupils ofthe school,old and new,will be sending him a present to mark the occasion.All those who h 求详解：Mr.Page will have been teaching for a total of forty years翻译过来是配齐先生已经执教满40年了为什么会要用will have been难道不是配齐先生将要完成40年的教师事业么?为什么会是已经完成呢 高二双曲线概念概念.公式 点. contribute sth to也可以说成contribute to 另外还有contribute sth towards和contribute towards sth这是新概念2册85课原文：I have just received a letter from my old school informing me that my former head- master,Mr Regmald Page,will b Mr.green will arrive ___Beijing this afternoon