	Affirmative	Negative	Question
	Subject + will have + past participle verb	Subject + will not have + past participle verb	Will + subject + have + past participle verb?
Examples:	By the time we arrive, he will have finished his work.	I will not have completed the project by the deadline.	Will you have finished your homework by the time we get home?
	They will have been married for 10 years next month.	He will not have graduated from college yet.	Will they have arrived by 6 p.m.?
	She will have written a novel by the end of the year.	We will not have seen each other for a year.	Will she have learned to play the piano by the end of the summer?

Usage:

Completed action in the future:

We use Future Perfect to talk about an action that will be completed at a certain point in the future.

Example: By the time you come back, I will have finished the report.

Probability:

We use Future Perfect to express a prediction or assumption about something that will happen in the future.

Example: She will have met him before, so she will know how to deal with him.

Hypothetical situations:

We use Future Perfect to talk about hypothetical situations that may or may not happen in the future.

Example: If I win the lottery, I will have travelled to all the continents by the end of the year.

Future before a specific time:

We use Future Perfect to talk about actions that will be completed before a specific point in the future.

Example: By the time the concert starts, the band will have rehearsed for 3 hours.

Usage Situation	Example
Completion of an action before a specific time in the future	By the time we arrive at the airport, the flight will have departed.
Prediction about a future action that will be completed before another action	By the end of the year, I will have saved enough money to buy a new car.
Expressing regrets or disappointment about an action that will be completed in the future	I’m afraid I won’t be able to attend your wedding. By the time you get married, I will have moved to another country.
Making assumptions about past actions or events in the future	When we meet tomorrow, I will have finished reading the book you recommended.

Adverbs and time expressions for Future Perfect:

by (a specific time):

By next week, I will have completed my project.

before (a specific time or event):

Before the concert starts, we will have eaten dinner.

by the time (a specific time or event):

By the time you arrive, I will have finished cooking.

when (a specific time or event):

When she comes home, I will have left.

by then:

By then, I will have already graduated.

already:

By next year, he will have already retired.

still:

By this time next year, I will still not have finished my degree.

yet:

By the end of the day, they will not have yet completed the project.

Future Perfect in subordinate clauses:

In a subordinate clause of time or condition, we do not use Future Perfect Instead, we use Present Simple, Present Continuous, or Present Perfect to talk about future events or actions that will take place before a certain time or condition is met.

For example, When we arrive at the airport, the plane will have already taken off. (Present Simple + Future Perfect)

Future Perfect with the modal verb must:

When the modal verb must is used with future perfect, it expresses a strong assumption or conviction about a completed action in the future.

For example, By next year, they must have finished building the new factory. (This sentence expresses a strong assumption or conviction that the construction of the new factory will be completed by next year.)

Using future perfect with must is not necessarily formal, but it can sound quite strong and certain. It’s often used in more formal or professional contexts, such as business or academic writing, where the speaker or writer wants to convey a high degree of confidence about a future event. However, it can also be used in informal settings to express a similar level of conviction or assumption about a future action.