Could / Can

[jack]

Are these correct? What do they mean?

1. I could take a shower right now.
2. I can take a shower right now.
3. I could have taken a shower right now.

[Mister Micawber]

(1) and (2) suggest present possibility; (2) also suggests present permission granted; (3) suggests present impossibility.

[Sathish Kumar]

Can and Could are 'model Auxiliary' verbs.
1. 'Could' in the first sentence suggests possibility that can still happen.
2. 'Can' in the second sentence suggests the ability.
3. 'Could Have Taken' suggests the possibility that could have happened, but not anymore.

Hope this is correct. Comment if any!!

[jack]

What do these mean? I know one is past tense and the other one is present but what else does it mean?

1. Aren't you tired form being all you could be?
2. Aren't you tried from being all you can be?

What do these mean?
3. I could make a change myself.
4. I can make a change myself.
5. I could finish my tasks in time.
6. I can finish my tasks in time.

[blacknomi]

1. Aren't you tired form being all you could be?

I am tired from being all I could be, I mean I would like to make efforts to do what I can do even if it's almost impossible.
As a teacher,
(1)I could be a mother at the same time who takes care of kids if I am teaching kids English.
(2)I could be a daughter when I teach a 60-year-old housewife.
(3)I could be a love consultant when I teach young adults who are dumped by their partners.
(4)I could be a idol when I have male students in my class.
(5)I could be a bonehead if it comes to any kewl techniques.

Notice, education is my pccupation so that I have to be a master of delivering knowledge that stores in my brain. Also I have to be responsible for class management, which can be frustrated once in a while. Okay, then, other roles that I could have to play such as a mother-could-be, daughter-could-be, love-consultant-could-be, idol-could-be and bonehead-could are not really my skills, but could be. :D

2. Aren't you tried from being all you can be?

The present auxiliary "can" is not that complicated than its past form "could." "Can" indicates the your capability of doing something, which means that you are able to do it. However, "could" could indicate the same thing just that it could be more imaginary like "I wish I could fly." Okay, back to your example senetence, "all I can be" sounds less imaginary than "all I could be" does.
As a teacher,
(1) I can be(yes, I am) a daughter in my family as well. ( But I'm not a love consultant though it could be.)
(2) I can be Patrick's romantic girlfriend as well.
(3) I can be a student when I am in a classroom Here


I can be someone else without making too many efforts.
I could be someone else with a little more imagination.

What do these mean?
3. I could make a change myself.
4. I can make a change myself.

As Mr. MM said, both indicate a possibility. Other than that, you would have to learn to feel the difference once in a while.
Could:
-might or might not.
-less subjective
-polite
-compromise
-indirect
-doubt

Can:
-be able to do something
-more subjective
-direct
-confident
-be sure of, definite
-promise, trustful

5. I could finish my tasks in time.
6. I can finish my tasks in time.

Can you tell me how do feel it? This is not an assigment of course.


Does that help, Jack?

[jack]

Thanks. Let me spend some time to think about it and I'll ask you if I have any questions. :)

[blacknomi]

You're welcome, Jack. Take your time.

I love your questions. :D

[Steven D]

What do these mean? I know one is past tense and the other one is present but what else does it mean?

1. Aren't you tired form being all you could be? <<


A - Aren't you tired from being all you were able to be. (possiblity in the past - or - ability in the past)

B - Aren't you tired from being all you can possibly be. (present possibility)

It depends on the context whether sentence 1 means A or B.


could - past ability

could - possibility in the past

could - possibility in the present

Once again, more context is needed to know which meaning "could" has.


2. Aren't you tried from being all you can be? <<


Aren't you tired from being all you are able to be.

Aren't you tired from being all you are capable of being.

can - present ability

What do these mean?

3. I could make a change myself. <<

It's possible for me to make a change.

4. I can make a change myself. <<

I am able to make a change. I am capable of making a change. I have the ability to make a change.

5. I could finish my tasks in time. <<

I was able to finish my tasks on time.

It's possible right now for me to finish my tasks on time.


6. I can finish my tasks in time.<<<

I am able to finish my tasks on time. I am capable of finishing my tasks on time.

[Tdol]

1. I could take a shower right now. (if I wanted to)
2. I can take a shower right now. (I have the opportunity)
3. I could have taken a shower right now. (I had the opportunity but didn't bother)

[jack]

What do these mean?

1. I guess I can go to school next year.
2. I guess I could go to school next year.

3. I guessed I could go to school next year.
4. I guessed I can go to school next year.

5. I can tell when my truck is going to lose traction.
6. I could tell when my truck is going to lose traction.