what is difference between could and would, and where we use them?
Part IV SHOULD and More Examples
I SHOULD study more to be a better student and I WOULD study more if I COULD find the time.
I COULD be a great scientist, and if only the teachers WOULD give me good grades in my classes,
I SHOULD be able to show all the world how brilliant I am.
I SHOULD save the poor, and if I knew morality I WOULD teach Morals to the wealthy,
and if I COULD persuade all the world to listen to me that I would tell everyone what they must do.
SHOULD anyone really listen to my ideas? Of course not. I have not established credibility, and I SHOULD first establish a great reputation and then I COULD persuade all people to listen to my ideas.
This SHOULD be easy for people to understand, and if they WOULD devote a little
time to study these issues they COULD grasp all of the concepts and teach them to others
COULD you swim as fast as an Olympic competitor? I know that I would not.
WOULD you like to go to a movie with me?
COULD you pay for both of us? I do not have much money right now.
(Answer) I COULD pay for both of us, but I WOULD not like to pay for both of us.
I WOULD prefer that you pay for yourself. Just because I COULD do something for you does not mean that I WOULD do something for you.
I COULD go to that movie with you, but I WOULD never go see that type of a movie.
I WOULD go to a movie with you if you COULD pick a different kind of movie for us.
Part III More Examples
You COULD go to medical school and become a Neurosurgeon; but just because you COULD to that, it does not logically follow that you would want to do that.
I hope this helps. Write again if you would have me offer more suggestions.
I COULD give more examples and I WOULD be very "willing" to help you if I COULD.
I WOULD help you if I COULD help you but you see I cannot help, because I COULD not think of enough answers to your question. If I COULD think of answers to your question, then indeed,
I WOULD help you. I WILL help you when I CAN help you; but perhaps in this instance I COULD not help you. I WOULD always try to help others if I COULD help others; but I cannot always help others even when I am "willing" to help others.
Part II WOULD
When you think of WOULD, you can think ink of its association with WILL
as in WILL POWER.
You can associate WOULD with WANT, which is another derivation of WILL.
When I WANT something, I am WILLING something.
Those things I WANT in life, I apply WILL to in life.
I WOULD have those things come true.
"I will write an answer to Kate, because I know an answer."
"I would write an answer to Kate, if I knew an answer."
"I will help because I can help." or "I would help only if I had the time to help."
"I WOULD have the world to be a peaceful place, because I WANT the world to be a peaceful place."
"I would get an answer to my question if only someone would help."
"I would speak English, if I could pronounce the words."
"I would answer your question if I knew the answer."
WOULD is stated to express "desire" or "intent".
Part I COULD
The dictionaries inform us that COULD shows "possibility"
or what can or could possibly be done.
"I could speak English if I was willing to study."
"I could master the language if I studied with great effort."
"I could answer your question if I knew the answer."
When you think of COULD, think of it in terms of a specific SKILL or POTENTIAL you have to do something.
If you were a lawyer, you COULD represent someone in a court of law; but that does not mean that you would want to represent an evil criminal in a court of law.
If you were a Queen, you COULD order the execution of any citizen of your country without a trial; but that does not mean that you would want to order the execution of any citizen of your country.
If you found a man that you liked for a friend, you COULD date that man; but that does not mean that you would want to date every man that you liked for a friend.
If you were wealthy, you COULD enter into the manufacture of a line of custom made exotic sports cars that cost $500,000 each; but that does not mean that you would want to do that simply because you COULD do that.
"could" and "would" are derivatives of "can" and "will".
So "could" is having the ability to do it and "would" is having the will to do it, or wanting to do it.