wǒ zhù de chéngshì bú dà, dànshì hěn ānjìng yě hěn ānquán.

Literally, 我住的城市 is something like the city [that] I live in.

The particle 的 links a description to a noun. In this sentence, 我住 describes 城市, so:

• 我住的 = that I live in
• 城市 = city

So the whole phrase means the city I live in.

This is a very common Chinese pattern:

• 我喜欢的书 = the book that I like
• 他买的车 = the car that he bought
• 我们去的地方 = the place we went to

Chinese puts the describing part before the noun, followed by 的.

This is a great question, because English speakers often expect a word-for-word equivalent of live in.

In Chinese, 住 can work naturally in a phrase like 我住的城市 without 在. This is the normal, idiomatic way to say the city I live in.

So:

• 我住的城市 = natural
• 我住在的城市 = generally unnatural in standard Mandarin

Even though 住在 is common in full sentences, such as:

• 我住在北京。 = I live in Beijing.

when you turn it into a modifying phrase before a noun, Chinese usually says:

• 我住的城市 not
• 我住在的城市

So this is something to learn as a pattern, rather than translating directly from English.

Because of a tone change rule called tone sandhi.

Normally, 不 is fourth tone: bù.
But when 不 comes before another fourth-tone syllable, it changes to second tone: bú.

Here:

• 大 = dà (fourth tone)

So:

• 不大 is pronounced bú dà

More examples:

• 不是 → bú shì
• 不要 → bú yào
• 不对 → bú duì

But if the next syllable is not fourth tone, 不 usually stays bù.

不大 literally means not big, while 小 means small.

In many situations, 不 + adjective sounds a little softer or less direct than using the opposite adjective.

So:

• 这个城市不大 = This city isn’t big
• 这个城市很小 = This city is small

These are similar, but 不大 can sound more neutral or mild. It does not always strongly emphasize smallness; it just says the city is not large.

This kind of softening is very common in Chinese.

Because in Chinese, many adjectives can act directly as the predicate of a sentence.

In English, you need a verb like is:

• The city is big
• The city is quiet
• The city is safe

In Chinese, adjectives often work by themselves:

• 城市很大
• 城市很安静
• 城市很安全

So in this sentence:

• 城市不大
• 很安静
• 也很安全

all work without 是.

If you say 是大 or 是安静, that is usually not correct in a normal sentence like this.

Not always.

In beginner vocabulary lists, 很 is often taught as very, and it certainly can mean that. But in simple adjective sentences, 很 is also often used just to make the sentence sound natural, without strongly emphasizing very.

So:

• 很安静 can mean very quiet
• but in context it can also just mean quiet

Likewise:

• 很安全 can mean very safe
• or simply safe

If you say just:

• 城市安静

it can sound incomplete, contrastive, or more literary depending on context. In everyday speech, Chinese usually likes a degree word such as:

• 很
• 非常
• 特别
• 真

So 很 here is partly grammatical and partly natural-sounding.

You usually repeat it because each adjective phrase stands on its own.

So this sentence has two parallel descriptions:

• 很安静
• 也很安全

That parallel structure sounds balanced and natural.

You might hear shortened speech in some contexts, but 很安静也很安全 is the cleanest and most standard version.

It is similar to English saying:

• quiet and also safe

rather than making the second part feel weaker.

也 means also.

In this sentence, it adds another description of the city:

• 很安静 = very quiet / quiet
• 也很安全 = also very safe / also safe

So the speaker is saying:

• the city is quiet
• and it is also safe

The placement is important. 也 usually comes before the part it modifies. Here it comes before 很安全:

• 也很安全 = also very safe

This is the natural position in Chinese.

但是 means but.

It connects two ideas that contrast with each other:

• 我住的城市不大 = The city I live in is not big
• 但是很安静也很安全 = but it is quiet and safe

The contrast is that the city is not big, yet it has positive qualities.

You could think of the overall meaning as:

• It’s not big, but it’s quiet and safe.

但是 is a common, neutral way to say but in Mandarin. A similar word is 可是, which is also very common in speech.

Because Chinese often omits repeated information when it is already clear from context.

The full version could be something like:

• 我住的城市不大，但是我住的城市很安静，也很安全。

But that sounds repetitive.

So Chinese naturally leaves out the repeated subject:

• 我住的城市不大，但是很安静也很安全。

English does this too sometimes, but Chinese does it even more often. Once the subject is established, later parts of the sentence often leave it unstated if there is no confusion.