zhèjiàn yīfu suōshuǐ le.

件 is a measure word (or classifier) for items of clothing and some other individual objects.

In Mandarin, when you say this / that / one / two + noun, you usually need a measure word between the number or demonstrative and the noun:

• 这件衣服 = this item of clothing
• 那件外套 = that coat
• 一件衬衫 = one shirt

So 这件衣服 follows the common pattern:

这 + 件 + 衣服

Using a measure word here is normal Mandarin grammar.

In standard Mandarin, 这 + noun usually needs a measure word in between, so 这个衣服 sounds unnatural.

The standard form is:

• 这件衣服

not

• 这个衣服

Why? Because 个 is a very general measure word, but clothing often has its own more natural classifier, such as 件.

A learner tip:

• 个 is often used when you do not know the correct classifier.
• But with common nouns like clothing, native speakers usually prefer the proper classifier.

So 这件衣服 is the natural way to say this piece of clothing / this garment.

衣服 can mean clothes, clothing, or sometimes a garment / an item of clothing, depending on context.

In this sentence, because it is preceded by 这件, it clearly refers to one specific item of clothing.

So:

• 衣服 by itself can be general: clothes
• 这件衣服 = this item of clothing

Mandarin nouns usually do not change form for singular and plural the way English nouns do. The classifier 件 already makes it clear that we are talking about one item.

Literally, 缩水 means something like shrink or contract after washing / exposure to water.

In everyday Chinese, it is very commonly used for clothes or fabric:

• 衣服缩水了 = the clothes shrank

The word is especially associated with fabric becoming smaller after washing.

It can also be used in other contexts, sometimes more figuratively, such as:

• money or value decreasing
• quantity being reduced

But in this sentence, with 衣服, the meaning is clearly to shrink in the wash / become smaller.

Here, 了 shows a change of state or a new situation.

So 这件衣服缩水了 does not just tell you that shrinking is an action. It tells you that the clothing has ended up in a shrunk state.

A very helpful way to think about it is:

• 缩水 = shrink
• 缩水了 = has shrunk / ended up shrunk / became shrunk

Important: this 了 is not simply a past tense marker. Mandarin does not mark tense the same way English does. Here, 了 mainly tells us that something has changed.

So the sentence focuses on the result:

• before: the clothing had its normal size
• now: it has shrunk

Yes, but it changes the feel of the sentence.

• 这件衣服缩水了 = this item of clothing has shrunk / ended up shrunk
• 这件衣服缩水 = this item of clothing shrinks / is prone to shrinking / shrinks as a characteristic, depending on context

Without 了, the sentence may sound more general or descriptive, like you are stating a property or tendency.

For example:

• 这件衣服会缩水。 = This item of clothing will shrink.
• 这件衣服容易缩水。 = This item of clothing shrinks easily.

But if you are reporting what happened to this specific piece of clothing, 缩水了 is the natural choice.

Mandarin word order is usually:

subject + predicate

Here:

• 这件衣服 = the subject
• 缩水了 = what happened to it

So the structure is:

这件衣服 + 缩水了 = This item of clothing + has shrunk

This is very similar to English word order:

This piece of clothing has shrunk.

Mandarin usually puts the topic or subject first, and then says what happened to it.

Here, 缩水 is functioning as a verb: to shrink.

So the sentence means that the clothing underwent the action/change of shrinking.

In Mandarin, many words can behave more flexibly than their closest English equivalents. A word that looks adjective-like in English may behave more like a verb in Chinese.

That is why you can directly say:

• 衣服缩水了

without needing a verb like became in between.

English often says:

• The clothes became smaller
• The clothes shrank

Mandarin can directly use 缩水 as the main predicate.

Yes, but the meaning is a little different.

• 缩水了 specifically suggests shrinking, especially fabric shrinking after washing or water exposure
• 变小了 just means became smaller

So:

• 这件衣服缩水了 = This item of clothing shrank
• 这件衣服变小了 = This item of clothing became smaller

If you want the natural word for clothes shrinking in the wash, 缩水了 is better.

Mandarin often does not need extra helper verbs where English does.

English says:

• This piece of clothing has shrunk
• This piece of clothing is shrunk or became shrunk in some contexts

Mandarin can simply say:

• 这件衣服缩水了

The idea of change/result is already expressed by:

• the verb 缩水
• the particle 了

So there is no need for a separate word equivalent to English has.

Also, Mandarin often omits forms of to be unless they are actually needed.

Both are related to natural pronunciation in speech.

The standard written form is:

• 这件 = zhèjiàn

But in fast or natural speech, 这 before a measure word is often pronounced more like zhèi:

• 这件 → sounds like zhèi jiàn

This is very common in spoken Mandarin.

So as a learner:

• recognizing zhè jiàn is fine
• hearing zhèi jiàn is also normal

The important thing is to understand the pattern:

• 这 + measure word + noun

Examples:

• 这个
• 这本书
• 这件衣服

All of these may sound slightly smoother in connected speech than the isolated dictionary pronunciation suggests.