Đầu gối của Lan đang đau.

A word-by-word breakdown:

• đầu gối = knee
• của = possession marker, like of
• Lan = Lan
• đang = marks something as currently happening or ongoing
• đau = hurt / painful / hurting

So the structure is basically:

knee + of Lan + currently + hurt

Natural English rearranges this as Lan’s knee is hurting or Lan’s knee hurts.

Because Vietnamese possession often works as:

thing possessed + của + owner

So:

• đầu gối của Lan = Lan’s knee
• literally: knee of Lan

This is different from English, where the owner often comes first: Lan’s knee.

You can think of của as a possession marker that links the thing to its owner.

Yes. đầu gối is a fixed noun meaning knee.

Even if learners notice that đầu often means head, you should learn đầu gối as one vocabulary item here. Many Vietnamese body-part terms are compounds, and the overall meaning is not always best understood by translating each small piece separately.

So in this sentence, just read đầu gối as knee.

đang shows that the situation is happening right now or is in progress.

So:

• Đầu gối của Lan đau. = Lan’s knee hurts / is painful
• Đầu gối của Lan đang đau. = Lan’s knee is hurting right now

In English, this often matches is hurting better than simple hurts, because đang adds a sense of current ongoing state.

It can feel like both, depending on how you compare it with English.

In sentences like this, đau describes a painful condition:

• Tôi đau. = I’m in pain / It hurts.
• Đầu gối của Lan đang đau. = Lan’s knee is hurting.

For English speakers, it is often easiest to think of đau as a word meaning hurt / painful, without worrying too much at first whether it is exactly a verb or an adjective. Vietnamese does not divide these categories in quite the same way English does.

Because Vietnamese often does not use a copula like English is/am/are in sentences of description or state.

English says:

• Lan’s knee is painful
• Lan’s knee is hurting

Vietnamese can simply say:

• Đầu gối của Lan đau
• Đầu gối của Lan đang đau

So the sentence is complete without a separate word meaning is.

Also, you would not normally use là here. Là is used in different kinds of sentences, such as identity or classification, not for this kind of physical state.

Yes, that is also possible and natural.

Compare:

• Đầu gối của Lan đang đau. = Lan’s knee is hurting.
• Lan đang đau đầu gối. = Lan has knee pain / Lan’s knee is hurting.

The first version focuses more on the knee itself. The second version focuses more on Lan as the person experiencing the pain.

Both are understandable and natural in many contexts.

Sometimes, yes, but it changes the nuance a little.

For example:

• Lan bị đau đầu gối.
• Đầu gối của Lan bị đau.

bị often adds a sense of being affected by something unpleasant or adverse. It can sound a little more like suffers from or is affected by pain.

But for a simple sentence like Lan’s knee is hurting, the original Đầu gối của Lan đang đau is already perfectly fine and natural.

Yes.

• Đầu gối của Lan đau. = Lan’s knee hurts / is painful
• Đầu gối của Lan đang đau. = Lan’s knee is hurting right now

Leaving out đang makes the statement more general or neutral. Adding đang emphasizes the current, ongoing situation.

In everyday speech, Vietnamese often omits time-marking words when the meaning is already clear from context.

A very common way is to add không:

• Đầu gối của Lan đang đau không? = Is Lan’s knee hurting?

You could also ask more naturally in conversation with:

• Đầu gối của Lan có đang đau không?

That has the same basic meaning, with a slightly fuller question pattern.

You can use không before đau:

• Đầu gối của Lan không đau. = Lan’s knee doesn’t hurt / is not painful.
• Đầu gối của Lan không đang đau is not the natural way to say it.

If you want to keep the idea of right now, a more natural phrasing would usually be:

• Bây giờ đầu gối của Lan không đau. = Lan’s knee doesn’t hurt now.

So in practice, you normally negate đau, not đang.

The pattern is:

noun phrase + đang + state

More specifically:

Đầu gối của Lan + đang + đau

This is a useful Vietnamese pattern for describing current conditions:

• Tôi đang mệt. = I’m tired right now.
• Cô ấy đang buồn. = She is sad right now.
• Tay tôi đang đau. = My arm/hand is hurting right now.

So this sentence is a very typical Vietnamese way to express a present physical state.

A rough English-friendly guide is:

• Đầu ≈ dow with a falling tone
• gối ≈ goy with a rising/creaky tone
• của ≈ koo-uh with a dipping tone
• Lan = Lan
• đang ≈ zahng / dang depending on accent
• đau ≈ dow

The tones matter a lot in Vietnamese, so it is best to listen to native audio and repeat the whole sentence as a chunk:

Đầu gối của Lan đang đau.

That will help more than trying to perfect each word only from English spelling.