[Grammar] I've forgotten where to put the keys...

[pseudo]

* I've forgotten where to put the keys.

What does the sentence above mean?

1. I've forgotten where I should put the keys.

2. I've forgotten where I had put the keys.

I think 'to infinitives with interrogative' has usually the future meaning.

ex) I don't know where to go. = I don't know where I should go.
I don't know when to start. = I don't know when I should start.

I think the sentence suggested means 2.(the past meaning)
But how can we distinguish between the two?
What does the sentence below mean?

* I asked him where to find the keys.

1'. I asked him where I could find the keys. (the future meaning)

2'. I asked him where he had find the keys. (the past meaning)

Thanks in advance.

 

[Barb_D]

It means that you have forgotten where the keys are supposed to go - where you should put the keys.

You are pet sitting for a friend. She told you to leave the keys somewhere. You forgot where. You text her: All is well. Chloe has been fed. But I have forgotten where to put the keys."

If you forgot where you put the keys, then "I forgot where I put the keys" is the way to say it.

 

[Barb_D]

What does the sentence below mean?

* I asked him where to find the keys.

1'. I asked him where I could find the keys. (the future meaning)

2'. I asked him where he had find the keys. (the past meaning)

Thanks in advance.

It means 1.

2 grammatically would be "I ask him where he had found the keys."

 

[pseudo]

s1. I asked him where to find the keys.

s2. I told him where to find the keys.

I thinks the subjects of each 'to find' is semantically different.
The s1's is 'I' and the s2's is 'him'
Does this difference only depends on the types of verbs?

 

[Barb_D]

s1. I asked him where to find the keys.

s2. I told him where to find the keys.

I thinks the subject[STRIKE]s[/STRIKE] of each 'to find' is semantically different.
The s1's is 'I' and the s2's is 'him' "he" not him when talking about a subject
Does this difference only depend[STRIKE]s[/STRIKE] on the types of verbs?

You're right:
1. I asked [him] where {I could} find the keys.
2. I told him where {he could} find the keys.

However, I don't understand your question.

Note that with "Does" you need the bare form of the verb - Does it depend, not Does it depends.

 

[pseudo]

Thank you for your indication.
Though it is very basic, I sometimes miss it.