Il future perfect simple si usa per:
By tomorrow he will have finished his work
He will have finished her homework by five o'clock
Next month I will have lived in London for five years
Il future perfect simple viene utilizzato spesso con i seguenti avverbi:
just (appena) -> nelle frasi affermative o interrogative
She will have just eaten by noon
Will she have just eaten by noon?
already (già) -> nelle frasi affermative
He will have already finished his homework by three o'clock
yet (già) -> nelle frasi interrogative (alla fine della frase)
Will they have finished their homework yet?
yet (ancora) -> nelle frasi negative (alla fine della frase)
They won't have finished their homework yet.
In una subordinata temporale,in inglese, non si usa il future perfect simple, ma il present perfect
You'll go out when you have finished your homework