geu sangja aneneun jageun bongtuga du gae deureo isseosseo.

Inside that box, there were two small envelopes.

Breakdown of geu sangja aneneun jageun bongtuga du gae deureo isseosseo.

• ~는: topic particle
• ~가: subject particle
• 작다: small
• ~에: location particle

Questions & Answers about geu sangja aneneun jageun bongtuga du gae deureo isseosseo.

What does 그 mean here? Is it that box or the box?

그 literally means that.

So 그 상자 is literally that box. In real translation, though, it can sometimes sound more natural as the box if the box has already been mentioned or is obvious from context.

So depending on context:

• 그 상자 = that box
• sometimes naturally translated as the box

What is 상자 안에는 made of?

상자 안에는 breaks down like this:

• 상자 = box
• 안 = inside
• 에 = in, at
• 는 = topic marker, often with a contrastive nuance

So 상자 안에는 means something like:

• inside the box
• as for inside the box
• in the box, ...

The 는 can add a slight feeling of setting the scene or contrasting that location with others, as if saying inside the box, there were...

Why are there both 는 and 가 in the same sentence?