应该是将来完成进行时,表示动作一直发生.比如,过去30年一直教书,或者过去十年一直有生意往来.
将来完成时,表示到那个时候,动作完成,没有表示过去一直发生的意思.
1 By the end of this year he 【will have been teaching】 for thirty years.
2 By this time next year, we 【will have been doing】business with each other for 10 years.