Transcript of SOS Grammar Lesson 1 - The Future Perfect Tense

G'day, you mob! Welcome to lesson one of S.O.S. Grammar.

So, today we're going to be covering the future perfect tense. We use the future perfect tense in English for actions that will be completed before a specific point in time in the future.

For example:

At 5pm, we will have left work.

She will have turned 25 by the year 2030.

The future perfect formula is 'will + have + the past participle of a verb'.

It doesn't matter if the subject of a sentence is singular or plural, the formula is always the same 'will + have + the past participle of a verb'.

So, when to use the future perfect tense.

Sometimes it's possible to use either the future perfect tense or the simple perfect tense interchangeably.

In the following examples, there's no real difference between the meaning because the word 'before' makes the sequence of events obvious.

The bus will leave before you arrive.

The bus will have left before you arrive.

However, when prepositions or clauses related to time like 'before', 'at 5pm', 'when', aren't used in phrases, the sequence of events isn't clear, and thus, you need to use the future perfect tense to indicate what happened first.

But most of the time, you're going to see both the future perfect tense used with these prepositions or future clauses that indicate a point of time in the future.

So, let's go through some examples comparing these two tenses and the different meanings, right? We're going to focus mainly, though, on the future perfect tense.

So, example no one. Imagine you are at a bus stop, you know, waiting for the next bus and you're wondering when it's going to leave. You could say something like:.

At 7PM, the bus will leave.

So, the bus will leave, it is going to leave, at exactly that time. At exactly 7PM.

But you could also say:

At 7PM, the bus will have left.

And this changes the meaning slightly. Now it means that when the clock strikes 7PM, the bus won't be there. It will have already left. Right? It's gone at 7PM. If you were to open your eyes at 7PM, the bus would be gone.

Example number two. Imagine you've caught a taxi to the airport to get a plane. You know, you're worried that you're going to be late. You could say:.

If you arrive on time, you'll get on the plane and the plane will take off.

All right? You arrive before the plane leaves and everything's successful.

If you arrive late, you won't get on the plane, because the plane will have taken off.

Right? So, at that point when you arrive, that action has already completed--the plane taking off. It's happened already. So:

If you arrive late, you won't get on the plane, because the plane will have taken off.

You've arrived and the plane has already gone.

Example number three, imagine that you're coming home from work to watch an episode of your favourite TV series on Foxtel and the episode starts at 5PM. You could say:

If you arrive home before the episode begins, you will see the episode.

However:

If you arrive home after the episode finishes, you will have missed the episode.

Right? And we could turn this into the negative where we say: 'you will have not seen the episode', 'you won't have seen the episode.'

So, we just use the negative form there of the future perfect by adding 'not' in front (after*) of the auxiliary verb 'will'. So, we have 'will not have' + 'the past participle'. This can also be written as 'won't have', plus the past participle of a verb.

Example number four. Imagine you're travelling from Victoria to Queensland to see your family on Christmas Day and they call you on the phone to try and work out when you're going to arrive so that they can plan when to schedule the party or the lunch.

And they suggest 12PM is the best time to do it. But, you know, you won't arrive before 2PM. So, if you were going to arrive at or after 2PM, you could say:

We'll need to have lunch after 2PM, because I won't get there until then.

However, if you knew for sure you would not arrive before 2PM, you could say:.

We'll need to have lunch after 2PM, because I won't have gotten there before then.

So, you'll notice the time clauses, the words related to time that we're using 'until' and 'before'.

So, we can also use inversions of both positive and negative phrases with the future perfect tense to create questions.

In order to create questions, you just need to reverse the order, or invert, the pronoun or noun and the auxiliary verb 'will' or in the negative form 'won't'.

So, the formula will be: Positive - 'will + the pronoun/noun + 'have' + 'the past participle'.

And in the negative, it'll be: 'won't' + 'the pronoun or noun' + 'have' + 'the past participle of a verb'.

Note: using the uncontracted 'will not' in these questions where they're inverted sounds very unnatural. We just don't do that. We will use 'won't'.

Let's start with some positive question examples.

So, example number five. You're coming home from work and you want to ask your husband if dinner will be ready by the time you arrive home. So, you might ask him something like:.

Will you have cooked dinner by the time I arrive home?

So, will you have completed the action of cooking dinner by that future point in time when I get home? He might respond:.

Yes, I'm going to start cooking dinner at 5PM. If you arrive home at 5L30PM, I will have already finished cooking dinner.

Right? So, by that point in time, in the future, 5:30PM, the action of cooking dinner will have been completed. It will have been completed by 5:30PM.

Example number six. Imagine that your kids are at school and they're learning about climate change and you know, they're worried about the world. Will it be worse off when they're adults? So, they might come home one day and ask you a series of questions like:

Will you have fixed climate change when I turn 20 years old?

Will the seas have risen in the year 2050?

Will the world have been ruined by the time I'm your age?

Will the ice caps have melted and completely gone?

Will all the animals in the Antarctic have become extinct?

Will carbon emissions have completely stopped after the year 2035?

Note how some of the nouns in these sentences can also be noun clauses with adjectives and other words added into them, as in the examples E and F here. Also, note how some of the verbs in the future perfect tense can be separated by words like adverbs, such as in the example F.

Now, let's go through some negative questions using the future perfect tense. Remember, for this, all we need to do is invert the pronoun or noun with the auxiliary verb 'won't', right? The contraction of 'will not'.

Example seven. Imagine you're that kid from the previous example asking the same questions. We could ask exactly the same questions, but use the negative form.

Won't you have fixed climate change when I turned 20 years old?

Won't the seas have risen in the year 2050?

Won't the world have been ruined by the time I'm your age?

Won't the ice caps have melted and completely gone?

Won't all the animals in the Antarctic have become extinct?

Won't carbon emissions have completely stopped after 2035?

Now, a few things happen when we use the negative form. Here, it indicates that I think all of these things are definitely going to happen. It's almost a sure thing, but I'm checking with you to see if you think differently.

And we can also use the negative form, and it doesn't change the fact that you're still asking effectively the same question as in the positive form, if you want to add disbelief or worry or even a little bit of pessimism to the question. So, you'll often hear this in the tone of voice when people ask questions too.

So, you could ask in the positive form:

Will the seas have risen in the year 2050?

But then we can use the negative form, if you're, say, a little sceptical, you know, you might say:.

Oh, won't the seas have risen in the year 2050?

Like, as if, "isn't that what you think?". Or you could say it in a sort of worried way.

Won't the world have been ruined by the time I'm your age?

You know, it's sort of like: "I think that's going to happen. It's going to happen, right? Isn't that what's going to happen?".

So, tone of voice here can change things as well as the negative sense at the start here when we use won't. But overall, it's effectively doing the same thing as a positive question. You're still asking that same question.

Example number eight. So, remember, back in example number four, where you're on the phone to your parents in Queensland trying to organise Christmas Day lunch. In order to check what time you'll arrive, they might ask you questions like:

Will you have arrived here by 12PM?

But they could turn this into a negative one if they assume you're going to arrive at 12PM, but something you've said or done makes them maybe think, eh, maybe that's not going to happen anymore. So, they might say are:.

Oh, won't you have arrived here by 12PM?

As if that's what they were expecting and now they kind of a bit confused.

And you could answer either positively or negative:

Oh, yeah, I'll have arrived by 12PM.

Or you could say:

Oh, nah, I won't have arrived by 12PM.

So, let's summarise the lesson.

We use the future perfect tense to place an action being completed before a certain point in time in the future.

Time clauses or prepositions like 'by 5pm', 'when', 'before', 'at lunchtime' are commonly used in phrases with the future perfect tense as the future point in time.

Both the future perfect and simple future tenses can sometimes be used interchangeably, as in, "the bus will leave before you arrive" or "the bus will have left before you arrive."

However, the simple future tense indicates something WILL HAPPEN exactly AT the future point in time you're talking about. For example, "I will cook dinner at 5PM." Five PM is when you plan to be cooking dinner.

Whereas the future perfect tense indicates that something WILL HAVE HAPPENED, or been completed, BEFORE the future point in time that you're talking about. For example, "I will have cooked dinner by 5PM." So, when it's 5PM, dinner will already be cooked.

When this distinction is important to make and you want to know if an action will have been completed before a future time, use the future perfect tense.