strong doubt about the present and past

[vil]

Dear teachers,

There are six statements:

1. He knows the language quite well.
2. He is waiting for someone.
3. He is still waiting for you ownstairs.
4. I have done it.
5. He did not notice you.
6. We did not see him do it.

Would you be kind enough to tell me whether I have expressed properly my strong doubt about the mentioned above statements in the following sentences below.

1.1. Can (could) he know the language quite well?
1.2. He can’t (couldn’t) know the language quite well.

2.1. Can (could) he be waiting for someone?
2.2. He can’t (couldn’t) be waiting for someone.

3.1. Can (could) she be still waiting for you downstairs?
3.2. She can’t (couldn’t) be still waiting for you downstairs.

4.1. Can (could) she have done it?
4.2. She can’t (couldn’t) have done it.

5.1. Can (could) he have failed to notice you?
5.2. He can’t (couldn’t) have failed to notice you.

6.1. Can (could) nobody have seen him do it?
6.2. Nobody can (could) have seen him do it.

Thank you in advance for your efforts.

Regards.

V.

[meez]

?

[Uncle M]

Can is present tense.
Could is past tense.

So if I am waiting downstairs, this is present tense so you would say
Can I be waiting downstairs?

If I was waiting downstairs, this is past tense and you would say
Could I be waiting downstairs?

So in the examples you give, the first 3 would be can and the second three could.

Dave

[Clark]

Dear teachers,

There are six statements:

1. He knows the language quite well.
2. He is waiting for someone.
3. He is still waiting for you ownstairs.
4. I have done it.
5. He did not notice you.
6. We did not see him do it.

Would you be kind enough to tell me whether I have expressed properly my strong doubt about the mentioned above statements in the following sentences below.

1.1. Can (could) he know the language quite well?
1.2. He can’t (couldn’t) know the language quite well.

2.1. Can (could) he be waiting for someone?
2.2. He can’t (couldn’t) be waiting for someone.

3.1. Can (could) she be still waiting for you downstairs?
3.2. She can’t (couldn’t) be still waiting for you downstairs.

4.1. Can (could) she have done it?
4.2. She can’t (couldn’t) have done it.

5.1. Can (could) he have failed to notice you?
5.2. He can’t (couldn’t) have failed to notice you.

6.1. Can (could) nobody have seen him do it?
6.2. Nobody can (could) have seen him do it.

Thank you in advance for your efforts.

Regards.

V.

I think all your sentences are correct. Just one small thing.

#6 We did not see him do it.

Can/Could any of us have seen him do it?
None of us can/could have seen him do it.

[vil]

Hi meez,

Expressing strong doubt about the statements made in the following sentences in present and past tense.

I hope this variant of the title will help you get out of the wood.

I am doing that by way of an apology for my original vague title.

Regards.

V.

[vil]

Hi Dave Mortimer,

Thank you for your prompt reply.

I am much obliged to you for taking keen interest in my unpretending efforts to assimilate the experience of NES’ in my favour. It did me a lot of good.

I know that "can" has two forms: "can" for the Present Tense and "could" for the Past Tense.

“I can’t explain it”said Threse. “I can’t explain anything I did to-day”.

He jumped as high as ever he could.

I know also that "can" expresses ability or capability, possibility, incredibility or doubt, astonishment.

When incredulity, doubt, or astonishment is expressed, the time of the action is indicated by the form of the infinitive and not by the form of the modal verb, as both “can” and “could” may refer to the present and to the past. In the action refers to the past, the Perfect Infinitive is used.

No wonder her father had hidden that photograph… But could he hate Jon’s mother and yet keep her photograph?

That is not true!”” exclaimed Linton, rising in agitation, “It cannot be; it is incredible, it cannot be.”

Can she be waiting for us?

She cannot be waiting for us.

Can (could) she have said that?

There could not have been such reelntless unforgiveness.

Can she have been waiting for us all the time?

She cannot have been waiting for us all the time.

Confusion came on Jon’s spirit. How could she say such things, just as they were going to part?

What could she have seen in that fellow Bosinney to send her mad?

In the last example we can easily replace could by can without any change of meaning. Thus, when expressing incredulity “could” loses its temporal meaning. “Could” with the Present Infinitive has almost the same meaning, only the negation is not so categoric as with “can”.

They saw us. I hope they didn’t recognize us.
The car was going too fast. They couldn’t have seen us.

Regards.

V.

[vil]

Hi Clark,

Thank you for your affirmative reply as well as for your well-meaning amendments.

Regards.

V.

[Clark]

Hi Vil

I had another look at my post and found out that my comment had two grammar mistakes. Sorry. That was stupid of me. Please see my edited post.

[riverkid]

Can is present tense.
Could is past tense.

So if I am waiting downstairs, this is present tense so you would say
Can I be waiting downstairs?

If I was waiting downstairs, this is past tense and you would say
Could I be waiting downstairs?

So in the examples you give, the first 3 would be can and the second three could.

Dave

Hi again, Dave.

This can't/couldn't be a matter of tense because in the examples that Vil gave both 'can' and 'could' can/could be used.

'can' illustrates a sense of greater reality, less doubt, [among other things] while 'could' expresses a more tentative stance, a more deferential feeling, a speaker who is less certain, [among other things].


1.1. Can (could) he know the language quite well?
1.2. He can’t (couldn’t) know the language quite well.

2.1. Can (could) he be waiting for someone?
2.2. He can’t (couldn’t) be waiting for someone.

3.1. Can (could) she be still waiting for you downstairs?
3.2. She can’t (couldn’t) be still waiting for you downstairs.

4.1. Can (could) she have done it?
4.2. She can’t (couldn’t) have done it.

5.1. Can (could) he have failed to notice you?
5.2. He can’t (couldn’t) have failed to notice you.

6.1. Can (could) nobody have seen him do it?
6.2. Nobody can (could) have seen him do it.

[vil]

Hi Clark,

Thank you again for your Slav largeheartedness. Thank you for your precisious.

There are further similar examples concerning "nobody" and "none of us":

None of us can judge None of us is in a position to judge.
None of us can put a price on the life of another another's life in God's domain, He loves us all. Nobody is worth more or less. ...

We drunk none of the wine that you brought.
We saw none of the students whom we had discussed earlier.
But
We saw no students.
We drunk no wine.

No one (or Nobody) came to visit me when I was in the hospital.
None of the books are mine.

Nobody tells me anything. (= People don’t tell me anything.)
None of the people I met were English.

Nobody in the class did their homework.

Neither of the children wants (or want) to go to bed.
Neither of us is (are) married.

Neither restaurant is expensive.

Regards.

V.