Future perfect and future continuous

Use will be + -ing for an action that will be in progress at a specific future moment — the future equivalent of the past continuous. It answers the question 'what will be happening at that time?'.

English also uses it for polite enquiries about plans and for events expected in the normal course of things. Asking what someone will be doing sounds softer than asking what they will do, because it enquires about the expected flow of events rather than pressing for a decision.

• At ten o'clock tonight, I'll be revising for my listening test.(in progress at a future moment)
• Will you be using the projector this afternoon, or can I borrow it?(polite question about plans)
• Don't call at noon — we'll be having lunch with the new interns.

Use will have + past participle for an action that will be complete before a future point. The action itself may happen at any time between now and then — what matters is that it will be finished by the deadline.

'By' is the tense's signature preposition: by Friday, by 2035, by the time you arrive. In IELTS it shines in predictions with dates and in describing milestones.

• By the end of this year, I will have saved enough for the flight to Toronto.(complete before a deadline)
• The decorators will have left by the time you get home.
• Scientists will have mapped the entire seabed by 2040, according to the project's timeline.

Will have been + -ing measures duration up to a future point — how long something will have lasted by then. It is rare in conversation but valuable when you want to stress an unbroken stretch of time.

Because the form is long, use it sparingly: one accurate example impresses; three in a row sound mechanical.

• By December, they will have been living in Manchester for a decade.(duration measured at a future point)
• When the rescue team lands, the sailors will have been drifting for two days.

Time clauses beginning with when, before, after, until, as soon as and by the time take a present tense, even though they refer to the future. The 'will' belongs only in the main clause.

This trap catches even strong learners, because many languages allow a future form in both halves. Train the pattern: by the time + present simple, … will have + participle.

• By the time you wake up, I'll have landed in Doha.(present simple in the time clause)
• By the time you will wake up, I'll have landed in Doha.(no 'will' after 'by the time')
• As soon as the results come out, we'll be celebrating.

Both tenses look forward from now, but they photograph the future moment differently. The future continuous freezes an action mid-flow at that moment; the future perfect looks back from that moment at what is already done.

Compare a single deadline: 'At 8 p.m. we'll be boarding' (in progress at eight) versus 'By 9 p.m. we'll have boarded' (complete before nine). Choosing the right viewpoint — not just the right form — is what earns the range credit.

• In July, she'll be doing an internship in São Paulo.(mid-flow view)
• By August, she'll have completed the internship.(looking back from a future point)