The future perfectThe aspect expressing completion. E.g.: He’s finished university. continuousThe aspect expressing duration, formed with be + verb-ing. E.g.: What are you doing? tenseA grammatical category that is marked by verb inflection. To express when an event or action happens in time or when a state exists, we use tenses. is used for eventA general term expressing that somebody or something does something or that something happens. E.g.: An apple fell on Isaac’s head.s which will have been in progressAn action is in progress when it is happening. E.g.: When I arrived he was surfing. ("he was surfing") at a definiteRelating to a specific or determined person, thing, idea or time. E.g.: I know the guy you are talking about. ("the guy you are talking about") point of timeA particular moment in time. E.g.: She came home at six. ("six") I was born in 1980. ("1980") in the future. It relates to the future perfect tense in the same way as the present perfect continuous relates to the present perfect, or the past perfect continuous to the past perfect (durationA concept, related to the continuous aspect, expressing that an action is in progress. E.g.: What are you doing? and result/completionA concept, related to the perfect aspect, expressing that an action has finished. E.g.: He’s finished university.). Note that although this tense is grammatically possible, it is rarely used by speakers of English.

By tomorrow it will have been raining for a fortnight.
Before the famine is declared, many people in the area will have been living with chronic malnutrition for some time.

Diagrams

Form: future perfect continuous
Future perfect continuous GOING TO