I've learning this damned language for three years, I should finally write at least one sentence without making mistakes!!!

Most people never learn a foreign language to perfection. But there is hope. Try Esperanto.

Esperanto is a pretty much non-language.

By the way, what is your first language?

al_ex_an_der, you're wrong.

Russian.

I think the reason Tatoeba suggests that members write only in their native language is that it is very difficult to construct natural-sounding sentences in a language other than one's native language. Languages have many nuances (subtle differences in meaning or expression)which come natural to native speakers but are very difficult for a non-native speaker to be aware of.
For this reason I have decided only to enter English sentences into Tatoeba, despite having "intermediate" German knowledge. :)

Astynk, you might hate me, but the dash seem to be quite Russian))

*seems (I have also been learning English for quite a few years))))

I hope you'll understand that we're seriously trying to make good reliable teaching materials for language learners. I simply wonder why you want to teach us English. I personally wouldn't use materials neither made nor checked by native speakers, and Tatoeba seems to assume that most learners are like me. Do you think this assumption is wrong? Wouldn't you mind using textbooks and dictionaries full of sentences that are considered unnatural by native speakers?