If you've forgotten anything, you can come right back and get it.

[lagoo]

Hi,

1. If you've forgotten anything, you can come right back and get it.

2. If you forget anything, you can come right back and get it.

What's the difference between sentence 1 and 2?

 

[Rover_KE]

Use #1 if they've already got to where they were going, and #2 if they haven't set off yet.

 

[lagoo]

Use #1 if they've already got to where they were going

Actually I heard this conversation from a TV drama in this situation: the husband wanted to move outside to live separately from the wife, and then the wife said the above-mentioned #1 sentence. When the conversation happened, they were still together.

 

[Matthew Wai]

The present perfect used in an if-clause should refer to the recent past.

 

[kadioguy]

The present perfect used in an if-clause should refer to the recent past.

But the OP said, 'When the conversation happened, they were still together'. So is it 'the recent past'?
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I just found this:

It says the present perfect can be used in the first conditional.

http://www.taiwantestcentral.com/Grammar/Title.aspx?ID=481

 

[Matthew Wai]

But there is no 'when' clause in the OP's if-clause.

 

[Matthew Wai]

The 'has stopped' above refers to the recent past.

 

[jutfrank]

Actually I heard this conversation from a TV drama in this situation: the husband wanted to move outside to live separately from the wife, and then the wife said the above-mentioned #1 sentence. When the conversation happened, they were still together.

Yes, this is the kind of situation I imagined when I first read 1.

I imagine the husband has packed his things and is just about to leave.

 

[lagoo]

Yes, this is the kind of situation I imagined when I first read 1.

I imagine the husband has packed his things and is just about to leave.

Your imagination is quite right.
And I hope my following understanding would be correct.

1. If you've forgotten anything, you can come right back and get it.
The speaker referred to a future time, which might be like "If you've forgotten anything when you get to your new place, you can come right back and get it."


2. If you forget anything, you can come right back and get it.
The speaker called the listener, and listener hadn't set off, which might be like "If you forget anything now, you can come right back and get it."

 

[Matthew Wai]

If you have gone to bed when I get home tonight, I'll be as quiet as I can.

If it has stopped raining by lunchtime, we can go shopping.

"If you've forgotten anything when you get to your new place, you can come right back and get it."

I think a time clause/phrase is needed for the present perfect to refer to the future.

 

[Matthew Wai]

Without context, I think the present perfect below refers to the recent past.

'If it has stopped raining, we can go shopping.'

 

[Matthew Wai]

I imagine the husband has packed his things and is just about to leave.

In this imagination, 'have forgotten' should refer to the recent past.
The husband has packed his things but could have forgotten something.

 

[jutfrank]

The speaker referred to a future time, which might be like "If you've forgotten anything when you get to your new place, you can come right back and get it."

I'd say the first clause probably refers to the present and the second clause refers to the future.

If you've forgotten anything, = if you are now unknowingly in a state of not having packed everything

you can come back and get it. = you have permission to come back later, after you realise something is missing

Of course, the moment of realisation takes place in the future.

 

[Matthew Wai]

If you've forgotten anything when you get to your new place, you can come right back and get it.

'When you get to your new place, if you discover you have forgotten anything, you can come right back and get it.'
I think 'discover' refers to the future, but 'have forgotten' does not.

 

[lagoo]

Finally I think I've got through it with all your help.

"If you've forgotten anything, you can come right back and get it."
1. You probably have forgotten something.
2. If condition 1 (the above sentence) is valid, then you can come right back and get it.

 

[lagoo]

If you've forgotten anything, = if you are now unknowingly in a state of not having packed everything

What if we say "If you forgot anything, you can come back and take it"?
I think this would be some kind of subjunctive mood, which always makes me out of my mind.

 

[Matthew Wai]

"If you forgotten anything, you can come back and take it"

The simple past of 'forget' is not 'forgotten'.

 

[jutfrank]

What if we say "If you forgot anything, you can come back and take it"?
I think this would be some kind of subjunctive mood, which always makes me out of my mind.

I don't recommend saying it like that, then!