USE 1 Duration before something in the future

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," "for two weeks," and "since Friday" are all durations which can be used with the Future Perfect Continuous. Notice that this is related to the Present Perfect Continuous and the Past Perfect Continuous; however, with Future Perfect Continuous, the duration stops at or before a reference point in the future.

Examples:

• They will have been talking for over an hour by the time Thomas arrives.
• She will have been working at that company for three years when it finally closes.
• James will have been teaching at the university for more than a year by the time he leaves for Asia.
• How long will you have been studying when you graduate?
• We will have been driving for over three days straight when we get to Anchorage.
• A: When you finish your English course, will you have been living in New Zealand for over a year?
  B: No, I will not have been living here that long.

Notice in the examples above that the reference points (marked in italics) are in Simple Present rather than Simple Future. This is because these future events are in time clauses, and you cannot use future tenses in time clauses.

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