[Grammar] Past tense vs Modal

[Mr. X]

Hello,

My first post here.

I am a little confused about when a verb is seen as modal and when as past tense. For instance, the dictionary says could could be both the past tense of can and a modal verb. So how do we know when to use which? For example, if I were to write something like this: The man could only smile.

What is the tense of the above sentence? Is it past tense, assuming could is the past tense of can? Or, is it present tense because the very same could as a modal verb can also be used in present tense?

Hope someone understands my confusion.

Regards,
Mr. X

 

[crazYgeeK]

"could" is usually used as the past form of "can". However, it can be used when you want to express (with no past tense meaning) :
1. The polite requests:
e.g: "Could you please ..." is more polite than "can you please.."
2. The possibilities in the present or future with a little certainty or doubtfulness:
e.g: "It could be about six o'clock" is used when you give out your guess on the present time.
"What are you going to wear to the party?
- I don't know. I could wear jeans, I guess"
3. Suppositions.
E.g: "Even if he had been there, he couldn't have helped you"
4. The indirect sentences.
E.g: He said he couldn't arrive before six o'clock
5. The conditional sentences.
"I could come earlier, if necessary"
"If you tried, you could do that work"

I hope this can help you.
Thanks

 

[Mr. X]

"could" is usually used as the past form of "can". However, it can be used when you want to express (with no past tense meaning) :
1. The polite requests:
e.g: "Could you please ..." is more polite than "can you please.."
2. The possibilities in the present or future with a little certainty or doubtfulness:
e.g: "It could be about six o'clock" is used when you give out your guess on the present time.
"What are you going to wear to the party?
- I don't know. I could wear jeans, I guess"
3. Suppositions.
E.g: "Even if he had been there, he couldn't have helped you"
4. The indirect sentences.
E.g: He said he couldn't arrive before six o'clock
5. The conditional sentences.
"I could come earlier, if necessary"
"If you tried, you could do that work"

I hope this can help you.
Thanks

Thank you. So in the above example of mine, it is past tense. Unless it is conditional, it isn't modal verb, then.

 

[Barb_D]

Hi, and welcome.

The man could only smile.

What is the tense of the above sentence? Is it past tense, assuming could is the past tense of can? Or, is it present tense because the very same could as a modal verb can also be used in present tense?

It could be either, and context tells you which.

I assumed it was the past of "can" -- which of course is also a modal:
Right now, he can only smile. There is nothing else he can do.
Back then, he could only smile and accept what was said. Now, he can fight back to show that the facts are on his side.

It's possible it's the conditional "could."
A: If he could only smile when we take his picture, he'd look so much better.
B: Yes, but he hates to have his picture taken.
A: Yes, I know. Who doesn't? But if he could only smile...

 

[Mr. X]

It's possible it's the conditional "could."
A: If he could only smile when we take his picture, he'd look so much better.
.

Thanks for your explanation. But when could is used as a modal verb, is the tense automatically present tense and must we add 'have' (such as could have, would have) to change it to past tense?

 

[Barb_D]

Again, "can" is a modal verb.

I can do it.
I could do it.

Both of those sentences are the modal verb "can," but the first is in the present and the second is in the past.

...when could is used as a modal verb, is the tense automatically present tense and must we add 'have' (such as could have, would have) to change it to past tense?

Basically, yes.

If you use "could" as the conditional modal, then it's present or future.
I could do it for you now, if you need me to.
We could do it tomorrow if you want to go to the movies today instead.

For a past conditional situation:
We could have been here two hours ago, if only you weren't too stubborn to ask for directions!
You could have waited for me! Instead, I had to pay $40 for a taxi ride home!

 

[Mr. X]

For a past conditional situation:
We could have been here two hours ago, if only you weren't too stubborn to ask for directions!
You could have waited for me! Instead, I had to pay $40 for a taxi ride home!

Thanks again for the detailed explanation, Barb_D. One more thing, though. I'll give an example to convey what I mean.
He hopes things could/would change. (present tense)
He hoped things could/would change. (past tense)

Though the second one is past tense (because of hoped), I am assuming one doesn't have to change 'could' to 'could have' because we're showing a future scenario in past tense, and hence only could/would is accurate. Am I right on this?

What I mean is: one can leave could/would/might etc. as they are, provided they are describing the future (even though from a past tense perspective). Another example: It was only a matter of time before he would shoot the prisoner. He wondered whether John might leave. (both sentences are in past tense, yet might/would are as they would be in present tense, since they're describing a possible future event).

Is my understanding correct? Sorry for the long post.

Thanks,
Mr. X

 

[Barb_D]

I was trying to think of when "I hope things could change" would work. I tried writing a little story, and it wasn't working. The "could" in the present represents a conditional. The problem seemed to be with "hope."

A: We're going to lose.
B: No, we can win! Things can turn around. We could win if the next batter hits a home run.
A: I hope we could win. -- This doesn't work.
A: I wish we could win... I wish I could believe that we'll get that home run. But I don't.

LATER:
A: I think we lost because you didn't believe we could win! (Past of "can.")
B: Sorry. I really wish I could have believed in that possibility, but I could not. (Past of "could.")