Learn French: Nous n'achetons pas d'ordinateur sans garantie. - We do not buy a computer without a guarantee.

In French, when you use sans (without) followed by a noun, you usually drop the indefinite article (un, une, or des). So instead of saying sans une garantie, you simply say sans garantie.

Why is it pas d'ordinateur instead of pas un ordinateur?

In negative sentences, the indefinite articles un, une, and des change to de (or d' before a vowel). Since we are saying we do not buy a computer, un ordinateur becomes d'ordinateur.

If I wanted to say 'with a guarantee', would I use an article?

Yes! The rule about dropping the article mainly applies to sans. If you were buying a computer with a guarantee, you would keep the article and say avec une garantie.

Why do both n'achetons and d'ordinateur have apostrophes?

Both ne and de drop their final e and add an apostrophe when the next word starts with a vowel sound. This is called elision, and it makes the sentence flow more smoothly when spoken.