"Carro" is the most common word in Spanish. "Auto" is known in many countries but the normal word only in Argentina and Chile (and Uruguay?). "Coche" is used in Spain, Equatorial Guinea and another country (Uruguay?), in other places it means "cart" (moved by horses) or special types of carts, like baby-carts.
I just said: "no I do not need the car". I was wrong! Its actually:"I do not need to use the car". Uh. Whats the difference,!
Its because 'Carro' is more widely used in spanish countries while in the few other countries 'Carro' means a cart.
That's what I thought,but I got marked wrong with out the "yo". Honestly, I don't worry much about punctuation on Duolingo, and as far as I can see it doesn't affect whether or not an answer is marked right or wrong. I understand English punctuation very well, and I just don't concentrate on it while I'm doing my Spanish lessons.
I may be wrong but I don't think this is a double negative as 'No' and 'I don't need to use the car' are two separate clauses. They emphasise and expand upon each other rather than cancelling each other out.
A double negative would be: 'I don't need no car.' Here, 'I don't need' and 'no car' would cancel each other out to mean that you do, indeed, need a car.