Grammar

Future Perfect tense

1,800 fill-in-the-gap exercises across 4 forms

For something that will already be done before a point in the future. It needs a deadline to measure against.

Pick a form to practice

When you need it

One job: to say that something will be complete before a stated future point.

By the time you read this, I will have left.

Used for:

• a deadline: The builders will have finished by August.
• an anniversary or a total: Next month she will have worked here for ten years.
• an assumption about the present: He will have landed by now.

The deadline is not optional

The tense compares two future points, so the second one has to be there:

• By six o’clock
• By the time the guests arrive
• Before the shop closes
• In three weeks

Without one, the sentence has nothing to point at, and the plain Future Simple is what you want.

by or until

This is the commonest error in the tense, and the two words are not interchangeable:

• by = not later than, a deadline. I’ll be back by six.
• until = the whole period up to then. I’ll be away until six.

The Future Perfect takes by, because it is about a deadline.

will have as a guess about now

A second use has nothing to do with the future. Will have often means I assume it has already happened:

Don’t call him — he will have gone to bed.

This is a confident guess about the present, and it is very common in speech.

Future Perfect or Future Perfect Continuous

Same split as with the other perfect pairs. The plain form counts the result; the continuous measures the time spent:

• By June he will have written three chapters.
• By June he will have been writing for two years.

All forms

Mistakes to avoid