wǒ bú tài xǐhuan zhème dà de chéngshì.

Because 不 changes tone before another fourth-tone syllable.

• 不 is normally bù
• 太 is tài (fourth tone)
• So 不太 is pronounced bú tài

This is a very common tone change rule in Mandarin.

Examples:

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

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

不太喜欢 means don’t really like or don’t like very much.

It is softer than plain 不喜欢.

• 我不喜欢... = I don’t like...
• 我不太喜欢... = I don’t really like... / I’m not very fond of...

So this sentence sounds a bit less direct and more natural in many situations.

Not exactly.

In 不太喜欢, 太 does not mean too in the usual English sense of excessively. Here it works more like a degree word, and the whole phrase 不太 + adjective/verb often means:

• not very
• not really

So:

• 不太好 = not very good
• 不太清楚 = not very clear
• 不太喜欢 = don’t really like

This is a very common pattern in spoken Mandarin.

这么 means this/so/such, depending on context.

In 这么大的城市, it means something like:

• such a big city
• a city this big
• so big a city

It modifies 大 and emphasizes the size.

Structure:

• 这么 + adjective + 的 + noun

Examples:

• 这么贵的东西 = something this expensive
• 这么难的问题 = such a difficult question
• 这么大的城市 = such a big city

的 links a modifier to a noun.

Here, 这么大 describes 城市, so 的 connects them:

• 这么大 = this big / so big
• 城市 = city
• 这么大的城市 = a city this big / such a big city

You can think of 的 here as turning the descriptive phrase into something that can directly modify the noun.

This pattern is very common:

• 漂亮的房子 = a beautiful house
• 很忙的人 = a busy person
• 这么大的城市 = such a big city

Normally, no. 这么大城市 sounds incomplete or unnatural in standard Mandarin.

With a phrase like 这么大 modifying a noun, 的 is usually needed:

• correct: 这么大的城市
• unnatural: 这么大城市

You may sometimes hear 的 omitted in certain fixed expressions or casual styles, but for learners, it is best to keep 的 here.

Both are possible, but they do different jobs.

1. 这么大的城市

   • this is a noun phrase
   • it means such a big city or a city this big
   • it can be the object of 喜欢

2. 城市这么大

   • this is a full statement
   • it means the city is this big

In your sentence, 喜欢 needs an object, so we use the noun phrase:

• 我不太喜欢这么大的城市。
• I don’t really like cities this big.

Chinese nouns usually do not change form for singular vs. plural.

So 城市 can mean:

• a city
• cities
• the city/cities, depending on context

In this sentence, it often has a general meaning:

• I don’t really like such big cities
• I don’t really like cities this big

Chinese leaves that number distinction more flexible than English does.

Because the sentence is not counting cities.

Measure words are used when you specify number or demonstratives like this, that, one, two, etc.

Examples:

• 一个城市 = one city
• 这座城市 = this city
• 那座城市 = that city

But here, 城市 is being described generally, not counted:

• 这么大的城市 = such a big city / cities this big

So no measure word is needed.

Yes. That would be perfectly grammatical.

The difference is tone and strength:

• 我不喜欢这么大的城市。

  • I don’t like cities this big.
  • more direct, stronger

• 我不太喜欢这么大的城市。

  • I don’t really like cities this big.
  • softer, more polite, less absolute

Native speakers often use 不太 to sound less blunt.

Both can mean so or that, but they differ in perspective.

• 这么 = this much / like this / so
  • often used for something close to the speaker, or something being emphasized right now
• 那么 = that much / like that / so
  • often used for something more distant, previously mentioned, or less immediate

Examples:

• 这么大 = this big / so big
• 那么大 = that big / so big

In many cases, both are possible, but 这么 often feels more immediate: a city this big.

In careful dictionary-style pronunciation, it is often given as xǐhuan, with the second syllable usually treated as neutral tone in normal speech.

So learners often hear:

• xǐhuan

rather than a full first tone on the second syllable.

This is common with many everyday two-syllable words in Mandarin: the second syllable can become lighter and less stressed.

Yes, but the meaning changes slightly.

• 大城市 = big city / big cities
• 这么大的城市 = such a big city / cities this big

这么大的城市 is more specific and expressive. It emphasizes the degree of size.

Compare:

• 我不太喜欢大城市。
  • I don’t really like big cities.
• 我不太喜欢这么大的城市。
  • I don’t really like cities this big.

The second one suggests the size feels especially large.

Yes, it is very natural.

It sounds like something someone might say when talking about lifestyle or preferences:

• 我不太喜欢这么大的城市。
• I don’t really like cities this big.

It is natural because:

• 不太喜欢 sounds polite and conversational
• 这么大的城市 is a normal descriptive noun phrase
• the word order is standard Mandarin

A native speaker could definitely say this in everyday conversation.