защото

защото

"Because."

In this case, 'защото' provides the explanation or justification for the lack of understanding.

Не разбрах защо ти е толкова важно, защото не ми обясни.

I didn't understand why it's so important to you, because you didn't explain to me.

Here, 'защото' connects the action of studying hard to its underlying purpose or reason.

Учих много усилено, защото искам да постигна добри резултати.

I studied very hard because I want to achieve good results.

In this sentence, 'защото' introduces a causal clause explaining the reason for not going to the party.

Не отидох на партито, защото бях зает.

I didn't go to the party because I was busy.