These days it's becoming more and more important to know English. It's hard to find place in which people don't know [lepiej: wouldn’t know] this language. In future English can become something like Esperanto – an international language that everybody should know.
It's true to say that learning English would [would? a nie: is?] be useful and relevant. On the first of May 2004 Poland joined the European Union and English is the main language used in the member countries of the community.
When you travel abroad you don’t need [bo ogólna prawidłowość] any other languages. You will certainly make oneself understood with English. What is more, then [unclear a bit, better: if you know English] you can make friends with people of other nations.
To get a good job, it's necessary to know at least two forEIGN languages. One of them is often English.
Learning new things broadens our minds and makes us more self-confident. So learn English! - it won't be a waste of the time!
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Konstruktywna krytyka? :)
Może w kwestii treści: Esperanto nigdy nie stał się lingua franca, więc nie wiem, czy używanie go jako jego synonimu jest poprawne.
>English is the main language used in countries that belong to the community
Yeah... But also French.