chuáng hěn dà.

Because in Mandarin, adjectives like 大 can act as the main predicate by themselves.

So English The bed is big is naturally:

床很大。

not:

床是大。 ❌

In Chinese, 是 is mainly used to link nouns to nouns, as in 他是老师 = He is a teacher.
But with adjectives such as 大 (big), 小 (small), 高 (tall), 漂亮 (pretty), you usually do not use 是.

Not always. In this sentence, 很 often does not sound as strong as English very.

In basic adjective sentences, 很 is often used to make the sentence sound natural and neutral:

• 床大 can sound abrupt or contrastive
• 床很大 sounds like a normal statement: The bed is big

So here, 很 is often closer to a light linking word than a strongly emphasized very.

If you really want to emphasize very big, you might say:

• 床非常大。
• 床特别大。

If you stress 很 in speech, then it can sound more like actual very.

Yes, but it depends on the situation.

床大 is grammatical, but by itself it can sound incomplete, contrastive, or like you are making a comparison:

• 床大，桌子小。 = The bed is big, and the table is small.
• 这个房间里床大。 = In this room, the bed is big.

For a simple neutral statement, learners are usually taught to say:

床很大。

That is the most natural beginner-friendly form.

Because this sentence means The bed is big, where 床 is the subject/topic and 很大 is the predicate.

The basic structure is:

noun + adverb + adjective

So:

• 床很大。 = The bed is big.

If you want to say big bed as a noun phrase, that is different:

• 大床 = big bed
• 很大的床 = a very big bed

So:

• 床很大 = The bed is big
• 大床 = big bed

Mandarin does not have articles like a, an, and the.

So 床 can mean:

• a bed
• the bed
• beds in some contexts

The exact meaning depends on context.

In 床很大, English will usually translate it as The bed is big or A bed is big, depending on the situation. Most often, in a simple standalone sentence, learners understand it as The bed is big.

By itself, 床 just means bed. It is a general noun.

Context tells you whether it is:

• a specific bed
• a bed in general
• the bed already mentioned

If you want to be more specific, you can add words such as:

• 这张床 = this bed
• 那张床 = that bed
• 一张床 = a bed / one bed

So 床很大 is natural when the bed is already understood from context.

Not in this sentence.

Measure words are needed when you use a number or a demonstrative like this or that:

• 一张床 = one bed
• 这张床 = this bed
• 那张床 = that bed

But in 床很大, there is no number or demonstrative, so no measure word is needed.

The common measure word for 床 is 张:

• 一张床

In English grammar terms, it is usually taught as an adjective: big.

But in Mandarin grammar, words like 大 often behave like stative verbs. That is why they can directly serve as the predicate of a sentence without 是.

So from a learner’s point of view:

• Vocabulary meaning: 大 = big
• Sentence behavior: it can function like the main verb/predicate in Chinese

That is exactly what happens in:

床很大。

The tones are:

• 床 chuáng — 2nd tone
• 很 hěn — 3rd tone
• 大 dà — 4th tone

A simple way to think of them:

• chuáng rises
• hěn is a low dipping tone, though in normal speech before another tone it is often pronounced as a low tone rather than a full dip
• dà falls sharply

So in natural speech, 很 in 很大 is often not fully pronounced with a dramatic dip. It is usually shorter and lower.

You say:

床不大。

Here 不 negates 大.

Notice that you normally do not say:

床不很大 ❌

That sounds unnatural in ordinary speech.

So:

• 床很大。 = The bed is big.
• 床不大。 = The bed is not big.

You can change 很 to other degree words:

• 床非常大。 = The bed is very big.
• 床特别大。 = The bed is especially big.
• 床太大了。 = The bed is too big.

Notice that 太...了 is a very common pattern:

• 太大了 = too big

So 床很大 is the neutral basic sentence, and you can swap in stronger words when needed.

Sometimes yes, sometimes no.

With a simple one-syllable adjective like 大, you can often say:

• 大床 = big bed

That is very common.

But if the modifier is longer or more descriptive, 的 is usually used:

• 很大的床 = a very big bed
• 漂亮的床 = a beautiful bed

So compare:

• 床很大。 = The bed is big.
• 大床 = big bed
• 很大的床 = a very big bed

Yes, absolutely.

It has everything needed for a simple statement:

• 床 = subject/topic
• 很大 = predicate

So it is a full, natural sentence meaning The bed is big.

Mandarin often allows very short sentences as long as the meaning is clear, and this is a standard example of that.