Use of  the Future Perfect Continuous:

We use the Future Perfect Continuous the same as the the Future Perfect Simple to make a forecast in the future to say that something will be in progress at a determined time in the future the Continuous form gives the action a duration. It is normaly used with the time expression beginnig with by: by then, by that time, by the 16th, by Monday, by this time tomorrow, by this afternoon/evening etc. This verb form is not very commonly used in present day English. Note! this tense is not used with state verbs (see Present Continuous) hate, seem, know, etc. When using these verbs we use the Present perfect Simple. Ex: Next month I will have been knowing Peter for two years. Incorrect  Next month I will have Known Peter for two years. Correct

• a forecast in the future with a duration

by the end of the month a will have been working here for three years.

Key words

.