It's because

#. It's because ~

~때문이야

 

I'm feeling really dizzy these days. * 어지러운

> It's because you don't eat enough vegetables.

Is it really because of that? * 그거 때문에

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It's because the air conditioner is on.

It's because it's 10 o'clock night.

It's because the baby is 1 month old.