geunyeoneun taekbaereul batgo aju gippeohaesseo.

They are particles, and they show the role of each noun.

• 그녀는: 는 marks 그녀 as the topic, roughly as for her or she
• 택배를: 를 marks 택배 as the direct object, the thing being received

So the structure is basically:

• 그녀는 = as for her / she
• 택배를 받고 = receiving the package / after receiving the delivery
• 아주 기뻐했어 = was very happy

받고 is the -고 connective form of 받다.

The ending -고 links one action to another, often like:

• and
• then
• after doing

So:

• 받다 = to receive
• 받고 = receive and / after receiving

In this sentence, 택배를 받고 아주 기뻐했어 means she received the package and was very happy, or more naturally, she was very happy after receiving the package.

It can suggest either, depending on context.

In many sentences, -고 simply connects two actions:

• 먹고 갔어 = ate and left

But in real use, it often also implies the natural order of events:

• first she received the package
• then she was happy

So here, 받고 is best understood as after receiving or having received, even though the grammar itself is the simple connector -고.

This is a very common learner question.

There are two related forms:

• 기쁘다 = to be happy, glad
• 기뻐하다 = to show/feel happiness, often used when talking about someone else's emotion

In Korean, when describing another person's feelings, speakers often use -어하다 forms like 기뻐하다, because you are usually describing an emotion you observe rather than directly feeling it yourself.

So:

• 나는 기뻤어 = I was happy
• 그녀는 기뻐했어 = She was happy / She showed happiness

Using 기뻤어 for a third person is not impossible in all contexts, but 기뻐했어 is very natural and common.

기뻐했어 is casual, informal speech.

It would be used with:

• close friends
• younger people
• diary-style narration
• casual storytelling

The polite version would be:

• 그녀는 택배를 받고 아주 기뻐했어요.

The plain dictionary form is:

• 그녀는 택배를 받고 아주 기뻐했다.

So the sentence you have is in a friendly, non-polite style.

택배 usually refers to:

• a delivery
• a parcel
• a package sent by courier

Depending on context, it can mean either:

• the package itself
• the delivery service/delivery item

In this sentence, 택배를 받다 most naturally means to receive a package/delivery.

So English translations like these all work depending on context:

• received a package
• got a delivery
• received the parcel

Grammatically yes, but in everyday Korean, 그녀 can sound a bit less natural than English she.

Native Korean often prefers:

• omitting the subject if it is clear
• using the person's name
• using a title or relationship term

So while 그녀는 is correct, everyday speech might more naturally say:

• 택배를 받고 아주 기뻐했어.
• 민지는 택배를 받고 아주 기뻐했어.

That said, 그녀는 is common in:

• written narratives
• translations
• stories
• situations where you want to clearly mark she

아주 means very.

It strengthens 기뻐했어:

• 기뻐했어 = was happy
• 아주 기뻐했어 = was very happy

It sounds fairly neutral and natural. Other possible intensifiers include:

• 정말 기뻐했어 = was really happy
• 너무 기뻐했어 = was so/too happy
• 무척 기뻐했어 = was very happy (a bit more formal/written)

Yes. That is also natural.

Compare the two:

• 택배를 받고 아주 기뻐했어
• 택배를 받아서 아주 기뻐했어

The -고 version simply links events:

• she received it and was happy

The -아서/어서 version can sound a little more like:

• she was happy because she received it
• or after receiving it

In this context, both are fine. The -고 version is simpler and more neutral as a sequence of events.

Yes, by default it is.

In this sentence, the natural reading is:

• 그녀는 received the package
• 그녀는 was very happy

When Korean connects verbs with -고, the subject usually stays the same unless the context clearly shows otherwise.

So here, the sentence means that she did both actions.

The structure is:

그녀는 + 택배를 + 받고 + 아주 + 기뻐했어

Broken down:

• 그녀는 = she / as for her
• 택배를 = the package/delivery (object)
• 받고 = receiving / after receiving
• 아주 = very
• 기뻐했어 = was happy

A natural structure description is:

Topic + object + action 1 + adverb + action/state 2

This is very common in Korean, where connected actions come before the final verb.

You can change the final ending.

Casual

• 그녀는 택배를 받고 아주 기뻐했어.

Polite

• 그녀는 택배를 받고 아주 기뻐했어요.

Formal written/narrative

• 그녀는 택배를 받고 아주 기뻐했다.

The rest of the sentence stays the same; only the final verb ending changes to match the speech level.

Yes, very often.

If it is already clear who you are talking about, Korean commonly drops the subject:

• 택배를 받고 아주 기뻐했어.

This can still mean She was very happy after receiving the package, as long as the context makes she clear.

This is one of the biggest differences from English: Korean often leaves out subjects and objects when they are understood.