I think that she meant "tak" instead of "taj".
1. "tak" means "yes", e.g.:
- Czy to jest zielone? Is it green?
- Tak. Yes, it is.
2. "tak" means "so" or "such" in such situations:
- To jest takie małe! It is so small!
- Jesteś tak głupi, że nie chcę z tobą rozmawiać. You're so stupid that I don't want to talk to you.
- On nie jest takim złym człowiekiem. He's not such a bad man.
3. you can use "tak" before that type of sentence: "I wish I..." to make it stronger, e.g.:
- Tak bym chciał pojechać do Nowego Jorku! How I wish I would go to NY!
4. "tak" means "in that way", "like this", e.g.:
- Zróbmy to tak... Let's do this like this...
5. "tak" in expression "... as well as..." or "both... and..." (tak..., jak i...), e.g.:
- Tak (or "zarówno") ja, jak i ty poszliśmy tam. Both me and you went there.
there are much more meanings of "tak" but they're not so important :)