Hello,
I dont know which one is right and why !!
car keys
keys car !!!
thanks
What has your question to do with the title of the thread?
Both 'car keys' and 'key cars' are possible, though they mean very different things. As is so often the case, context is vital.
Context is always important; labelling is rarely important.
The keys that unlock the car are car keys.
[Not a teacher]
I've read somewhere that "key cars" means to scratch cars using a key. Is it correct?
Yes, if you come out of your house and find a long thin scratch down the side of your car, you would say "Some b*stard has keyed my car!" (or something slightly politer of course).
Except for certain special cases (e.g. Attorney General), in English adjectives go before the noun they describe, not after. So it's a blue car, not a car blue. It's car keys (keys for a car). It's a tennis racket (racket for playing tennis).