Cậu tráng sạch chai nhựa nhé.

Cậu is a second-person pronoun meaning you, but it is not neutral in all situations.

In this sentence, cậu is typically used:

• between friends
• with someone of a similar age
• sometimes to someone younger in a casual way

So the sentence sounds familiar and informal, not like something you would normally say to a stranger, a boss, or an older person.

A very rough comparison in English would just be you, but Vietnamese pronouns also show relationship and social closeness.

Tráng usually means to rinse or to swish water around and wash lightly, often as a quick cleaning step.

By contrast, rửa is a broader word meaning to wash.

So:

• rửa chai = wash the bottle
• tráng chai = rinse the bottle

In this sentence, tráng suggests rinsing the plastic bottle out, rather than giving it a full scrub.

Sạch means clean, but here it is not just a separate adjective describing the bottle. It works like a result complement: it tells you the result of the action.

So tráng sạch means:

• rinse it clean
• rinse it thoroughly
• rinse it so that it becomes clean

This is very common in Vietnamese:

• lau sạch bàn = wipe the table clean
• rửa sạch tay = wash your hands clean
• quét sạch sàn = sweep the floor clean

So in tráng sạch chai nhựa, the idea is not just rinse the bottle, but rinse the bottle until it is clean.

Vietnamese often puts a result word like sạch right after the verb.

So the pattern is often:

verb + result + object

Examples:

• lau sạch bàn
• rửa sạch bát
• quét sạch nhà

That is why tráng sạch chai nhựa sounds natural.

If you say tráng chai nhựa sạch, it sounds less natural in standard usage because sạch is usually tied closely to the verb as the result of the action.

It can mean either, depending on context.

Vietnamese nouns usually do not mark singular vs. plural the way English does. So chai nhựa could mean:

• the plastic bottle
• a plastic bottle
• plastic bottles in some contexts

In this sentence, most learners will understand it as the plastic bottle or a plastic bottle, depending on the situation.

If the speaker wanted to make it clearly plural, they might say something like:

• những chai nhựa = plastic bottles
• mấy chai nhựa = a few plastic bottles

No. Here chai is the noun bottle.

So:

• chai nhựa = plastic bottle

This is not the same as a classifier structure like:

• một chai nước = a bottle of water

In một chai nước, chai works more like a container noun/classifier meaning bottle. But in chai nhựa, it simply means the object itself: a bottle made of plastic.

Nhé is a sentence-final particle that softens the sentence and makes it sound friendlier, gentler, or more persuasive.

In this sentence, it adds a feeling like:

• okay?
• please
• all right?
• for me, okay?

It often appears in requests, suggestions, and reminders.

Compare:

• Cậu tráng sạch chai nhựa. = more direct, plain statement/command
• Cậu tráng sạch chai nhựa nhé. = softer, friendlier, more natural in conversation

So nhé does not change the core meaning much, but it changes the tone a lot.

Yes, it functions like an imperative or request.

Vietnamese often gives commands without a special imperative verb form. Instead, the meaning comes from context, word choice, and particles like nhé.

So Cậu tráng sạch chai nhựa nhé is basically:

• a request
• a gentle instruction
• a casual command

It sounds less harsh than a bare order because of cậu and especially nhé.

It is casual and friendly, not highly formal.

Why?

• cậu is an informal pronoun
• nhé softens the sentence
• the whole sentence sounds like something you say to a friend, classmate, sibling, or someone close

It is polite in a casual way, but not formal-respectful. You would usually choose different pronouns for older people, customers, superiors, or strangers.

For example, with a more respectful pronoun, the sentence might change significantly.

Vietnamese often does not need a direct equivalent of English please.

Politeness is often shown through:

• pronouns
• sentence-final particles
• tone of voice
• context

In this sentence, nhé helps do some of the work that please does in English.

So even without a separate word meaning please, the sentence can still sound polite and natural.

Yes, very often tráng chai suggests rinsing out the bottle, especially the inside, though context matters.

Because bottles are containers, tráng often implies:

• rinse it out
• swish water through it
• clear out residue inside

If the speaker wanted to emphasize a more complete washing of the whole bottle, they might use rửa sạch chai nhựa instead.

So tráng sạch chai nhựa often gives the sense of rinse the plastic bottle clean, especially as a practical cleaning step.

Yes, that is a very good close translation.

Possible natural translations include:

• Rinse the plastic bottle clean, okay?
• Please rinse the plastic bottle thoroughly.
• Rinse out the plastic bottle, okay?

Each version highlights a slightly different nuance:

• rinse ... clean matches tráng sạch well
• please helps reflect the soft tone of nhé
• okay? is also a nice way to reflect nhé

Not necessarily. Hãy can mark an instruction or encouragement, but in everyday speech it is often unnecessary and can sound more formal, deliberate, or textbook-like.

So:

• Cậu tráng sạch chai nhựa nhé. = very natural, casual
• Cậu hãy tráng sạch chai nhựa nhé. = still understandable, but a bit more marked

In many real-life conversations, the version without hãy sounds more natural.