Future Perfect Tense  

What is the future perfect tense?

We use the future perfect tense to say that something will finish or be completed at a specific point in the future. We also often include durations of time to indicate how long something has been happening once a future moment in time is reached.
In addition, we can use the future perfect tense to make a present prediction about something that we believe has or should have happened in the past.
The most common way we create the future perfect tense is by using the modal auxiliary verb will + have + the past participle of the verb. For example:
  • “This June, I will have lived in New York for four years.”
  • “You will have heard by now that the company is going bankrupt.”
  • “She’ll have slept for the whole day if she doesn’t get up soon!”

Functions of the Future Perfect

Actions completed in the future

We often use an adverbial expression of a future point in time with the future perfect tense to describe when an action will be completed or accomplished. This adverbial phrase can occur either before or after the future perfect verb. For example:
  • “With the way you’re spending money, you will have gone through your savings in less than a month.”
  • After this next race, I will have completed 10 triathlons.”

Future spans of time

The future perfect tense is often used to indicate a point in the future at which a certain action or situation will have been happening for a given length of time. For example:
  • “It’s hard to believe that by next month we’ll have been married for 10 years.”
  • “I will have worked on this ranch for more than half my life when I turn 40.”
As we can see above, the adverbial phrase expressing the duration of time (“for 10 years,” “for more than half my life”) usually comes after the future perfect tense construction. The expression of the future point in time (the point at which the duration is accomplished) can appear either before or after the future perfect tense.

Present predictions of past actions

We also use the future perfect for a present prediction of something we believe has already happened in the past. If we include adverbials related to time, we generally include expressions related to the present time rather than the future. For example:
  • “You will have seen on page 18 how to set up the computer.”
  • “Your mother will have left the dentist’s by now.”
  • At this stage, everyone will have heard the rumors already.”

Other sentence types

Negative sentences

To describe something that will not be completed at a point in the future, we make the future perfect tense negative by adding not after the modal verb will (usually contracted as won’t). For example:
  • “Why are you going to the airport so early? Her flight will not have arrived yet.”
  • “At this rate, I won’t have finished half of the work I need to get done by tomorrow.”

Interrogative sentences

We can ask whether an action will be complete in the future by inverting will with the subject, as in:
  • Will they have read the memo ahead of the meeting?”
  • Will you have had something to eat before you arrive?”
We can also ask about specific aspects of a future action by using different question words or phrases. Remember, we still invert will with the subject in this case:
  • What will we have learned from such tragic events as these?”
  • Who will have prepared the notes for the seminar?”
  • How much money will we have spent trying to get this car working?”
  • How long will you have worked there before your maternity leave begins?”

Other constructions

Although we most commonly use the modal verb will, there are two other ways we can form the future perfect tense: be going to and shall.

Be going to

Be going to can only form the future perfect tense when it is used to describe an action that finishes in the future—in this way, it is interchangeable with will in meaning.
We usually contract be with the subject when we use be going to. For example:
  • “She’s going to have won nine championship titles by the time she’s 25.”
  • “If you keep reading at that pace, you’re going to have finished the book before the rest of the students.”
However, using be going to can sometimes result in an awkward construction, and it is not as common as will. We also cannot use the be going to construction when talking about something that we predict to have happened in the past.

Shall

We can also use the modal verb shall instead of will to form the future perfect tense in formal speech or writing. Unlike be going to, we can use shall for all uses of the future perfect. For example:
  • “By next spring, I shall have lived on my own for nearly a decade.”
  • “The students shall have finished their evaluations this time next week.”
  • “You shall have heard, no doubt, the unflattering remarks made about my character.”
However, this creates a very formal tone that is not common in modern English; as a result, will + have + past participle remains the most common construction of the future perfect tense.
Quiz

1. Which of the following modal auxiliary verbs is used to create the future perfect tense?





2. Which of the following is not a function of the future perfect tense?





3. How does the structure of the future perfect tense change in an interrogative sentence?





4. For what purpose can we use shall instead of will to form the future perfect tense?





5. When are we not able to use be going to instead of will to form the future perfect tense?




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