Future Perfect Continuous

IMPORTANT:   No Future in Time Clauses

Like all future forms, the Future Perfect Continuous cannot be used in clauses beginning with "when," "while," "before," "after," "by the time," "as soon as," "until," "if" and "unless". In this lesson, all verbs in Time Clauses are italicized.

EXAMPLES:

I won't tell the student the answer until he has been working on the math problem for more than an hour. Correct

I won't tell the student the answer until he will have been working on the math problem for more than an hour. Not Correct

IMPORTANT:   No Future in Time Clauses

Like all future forms, the Future Perfect Continuous cannot be used in clauses beginning with "when," "while," "before," "after," "by the time," "as soon as," "until," "if" and "unless". In this lesson, all verbs in Time Clauses are italicized.

EXAMPLES:

I won't tell the student the answer until he has been working on the math problem for more than an hour. Correct

I won't tell the student the answer until he will have been working on the math problem for more than an hour. Not Correct

FORM:   Future Perfect Continuous

[WILL HAVE BEEN] + [VERB + ing]

EXAMPLE:

I will have been waiting for two hours when her plane finally arrives.


[AM / IS / ARE] + [GOING TO HAVE BEEN] + [VERB+ing]

EXAMPLE:

I am going to have been waiting for two hours when her plane finally arrives.

NOTE: It is possible to use either "will" or "going to" to create the Future Perfect Continuous with little or no difference in meaning.

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 the duration stops in the future.

EXAMPLES:

They will have been talking for over an hour by the time Tony arrives.

She is going to 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.

USE 2:   Cause of Something in the Future

Using the Future Perfect Continuous before another action in the future is a good way to show cause and effect.

EXAMPLES:

Jason will be tired when he gets home because he will have been jogging for over an hour.

Claudia's English will be perfect when she returns to Germany because she is going to have been studying English in the United States for over two years.

IMPORTANT

If you do not include a duration such as "for five minutes," "for two weeks" or "since Friday", many English speakers choose to use the Future Continuous. There is also a difference in meaning. Compare the examples below.

EXAMPLES:

I will be reading when my roommate returns.
The reading will be interrupted.

I will have been reading for an hour when my roommate returns.
The reading will stop just before my roommate returns.

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