"Chceš jít na záchod?"

Translation: Do you want to go to the bathroom?

[NinaOBel]

Why don't you receive WC for toilet?

[King2E4]

WC is an abbreviation. Duolingo doesn't accept abbreviations.

[piotr_siudak]

Seriously, I can understand "bathroom" (although zachod is not the place you bathe) but how come "lavatory" is not accepted answer and toilet is?

[VladaFu]

It is now accepted. It was probably missing and was added at some point, not sure when.

[jenda48]

"Do you want to go to the toilet?" is OK, thanks. And I think that it is polite and exactly.

[BrianSille2]

This is a room drowned in euphemism. In some areas "going to the toilet" is the euphemism for the physical activity that takes place there, and might not therefore be acceptable in polite society. Toilet, bathroom and lavatory all mean basically a place to wash. Czech is fortunate in having a specific word for the room although it is itself a euphemism, meaning, I believe, a secluded place (like latrine in English)

[VladaFu]

Czech people may have an impression that "toilet" is a high-society word like "toaleta" in Czech and that is not the case. Especially not in America.

There are many synonyms and hyponyms with various level of politeness in Czech (see https://en.wiktionary.org/wiki/z%C3%A1chod).

For Jenda: "Do you want to go to the toilet?" is accepted here.

[StephenMil224287]

In colloquial english you would say, he wants to go to the loo. Probably derived from Waterloo (Battle of).

[BoneheadBass]

"Loo" is also accepted. It used extensively in BrE, but much less often in AmE.

[BrianSille2]

or from a vulgar song referring to a facility on the road to a railway station of the same name?