If you know football really well, then you could/can/would/will probably explain it to a non-fan.
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(Native American English speaker)
I like Omni's answer, I am only adding onto it.
I want to offer an example where "could" and "can" can't be interchanged.
I'm so hungry I could eat a horse.
This is an idiom. I am very hungry, to the point where if I wanted to I could eat an entire horse. However "I'm so hungry I can eat a horse" sounds wrong and "I can eat a horse" would mean something entirely different. If you are so hungry that you could eat a horse, you aren't meaning this literally. If you say you can eat a horse, you mean that you literally are capable of eating a horse. Could's emphasis is on intent where can's emphasis is on ability. "I could eat a horse" means that you're hungry. "I can eat a horse" means that you have an extremely large stomach.
Here's an example where would and will can't be interchanged.
If I were you, I would go to the doctor.
I can't possibly be you and go to the doctor. In this hypothetical situation where I am you, I would go. But I can't possibly be you, so "will" doesn't make sense. Will means that I am going to, there is no hypothetical situations.
"If my condition gets worse, I will go to the doctor" is okay because it is a definite, expected thing to do.
Here's an example where would and could can't be interchanged.
If I won a million dollars I could buy a Ferrari.
That doesn't mean I necessarily am going to buy a Ferrari, it's just an option. If I said "If I won a million dollars I would buy a Ferrari", I mean that I necessarily am going to buy a Ferrari. I will buy a Ferrari.