Tôi hút bụi trong phòng khách.

Yes—hút bụi is best learned as a set verb phrase.

• hút = to suck / inhale
• bụi = dust

So literally it is something like suck dust, but in normal Vietnamese it means to vacuum or to do the vacuuming.

You will also see:

• máy hút bụi = vacuum cleaner
  (literally dust-sucking machine)

So even though it has two words, learners should usually treat hút bụi as one action.

Because Vietnamese verbs do not change form for tense the way English verbs do.

hút can mean:

• vacuum
• am vacuuming
• vacuumed
• will vacuum

The exact time usually comes from:

1. context
2. time words
3. aspect markers

For example:

• Tôi đang hút bụi trong phòng khách. = I am vacuuming in the living room.
• Tôi đã hút bụi trong phòng khách rồi. = I already vacuumed in the living room.
• Tôi sẽ hút bụi trong phòng khách. = I will vacuum in the living room.

So the plain sentence is neutral and depends on context.

It is a location phrase.

• trong = in / inside
• phòng khách = living room

So trong phòng khách means in the living room.

Grammatically, this phrase tells you where the action happens. It is not the direct object of the verb.

That is why the sentence is more literally:

• I vacuum in the living room

But English often translates it more naturally as:

• I vacuum the living room

So the English meaning may sound slightly different from the Vietnamese structure.

Yes, very often you can.

• ở phòng khách = at/in the living room
• trong phòng khách = inside the living room

The difference is small:

• ở is more general for location
• trong emphasizes being inside the space

Both are natural in everyday speech.
For this sentence, both would usually be understood well.

Literally:

• phòng = room
• khách = guest

So phòng khách literally means guest room, but in modern Vietnamese it normally means living room or reception room—the room where guests are received.

So this is one of those cases where the literal parts are useful to know, but the natural meaning is more important.

Vietnamese usually does not use articles like English a/an/the.

So phòng khách can mean:

• a living room
• the living room
• sometimes even my/our living room, if the context already makes that obvious

If you want to be explicit, you can add more words:

• phòng khách của tôi = my living room
• cái phòng khách đó = that living room

But in many everyday sentences, Vietnamese leaves this unstated.

Tôi is a common, neutral, and polite way to say I, especially in textbook Vietnamese and in situations where you want to sound safe and respectful.

However, Vietnamese pronouns depend a lot on:

• age
• relationship
• social situation

In real life, people may use words like:

• em
• anh
• chị
• con
• cháu
• mình

So tôi is correct here, but it is not the only possible first-person word. It is often a bit more formal or neutral than what close friends or family would use.

The sentence follows a very common Vietnamese pattern:

Subject + verb phrase + location

So here:

• Tôi = subject
• hút bụi = verb phrase
• trong phòng khách = location

This is fairly straightforward for English speakers because the order is quite similar to English.

Yes. hút has a broader meaning than just vacuum.

Depending on context, it can mean:

• to suck
• to inhale
• to smoke

For example:

• hút thuốc = smoke cigarettes
• hút bụi = vacuum

So the second word is very important.
When you hear hút bụi, Vietnamese speakers will understand it as the vacuuming action, not smoking.

Add đang before the verb phrase:

• Tôi đang hút bụi trong phòng khách.

đang marks an action that is in progress, similar to English am/is/are ... -ing.

So:

• Tôi hút bụi trong phòng khách. = neutral; could be habitual or context-based
• Tôi đang hút bụi trong phòng khách. = clearly happening right now

This is a very common and useful upgrade to the sentence.

Yes—very much. Vietnamese is a tonal language, so changing a tone can change the word.

In this sentence, several words have different tones:

• tôi = no tone mark
• hút = acute accent
• bụi = dot below
• trong = no tone mark
• phòng = grave accent
• khách = acute accent

For a beginner, the most important thing is:

1. notice that every syllable has a tone
2. do not ignore the tone marks
3. practice the whole phrase, not just isolated words

Even if your grammar is correct, wrong tones can make the sentence hard to understand.