We use the FUTURE Perfect Continuous to show that something WILL CONTINUE up until a particular event or time in the future. For” five minutes” “since Friday “and “for two weeks” are both durations which can be used with the Future Perfect Continuous. Notice that this is related to the Present Perfect Continuous; however, the duration does stops at or before a reference point in the future. The future perfect continuous is composed of two elements the future perfect of the verb “to be” (will have been) + the present participle of the main verb (base + ing)
Future Perfect Continuous Tense
