Learn Hardcore Chinese: Tā juéde chuān lánsè de yīfu bǐ chuān hóngsè de yīfu gèng héshì. - He thinks wearing blue clothes is more suitable than wearing red ones.

比 (bǐ) marks a comparison: A 比 B + adjective = “A is more ADJ than B.”
Here, 穿蓝色的衣服 (wearing blue clothes) is A, 穿红色的衣服 (wearing red clothes) is B, and 更合适 (even more suitable) is the adjective phrase.
So: “Wearing blue clothes is (even) more suitable than wearing red clothes.”

Why is 更 used when we already have 比? Is it redundant?

更 (gèng) adds emphasis: “even more.”

A 比 B 合适 = A is more suitable than B.
A 比 B 更合适 = A is even more suitable than B (stronger).
You can use 更/还/更加 for extra emphasis, or omit them for a plain comparison.

Can I drop the repeated 穿 and 衣服 to avoid redundancy?

Yes. Common, natural alternatives include:

他觉得穿蓝色的衣服比红色的更合适。
他觉得穿蓝色的比穿红色的更合适。
他觉得穿蓝色的比红色的更合适。
Here, 的 stands for “one(s),” so you don’t need to repeat 衣服.

What does 的 do after the color words? Why not 得 or 地?

Here 的 is the attributive marker linking a modifier to a noun: 蓝色的 (blue) + 衣服 (clothes).

的: before nouns (attributives), as in 红色的衣服.
地: before verbs (adverbials), e.g., 认真地学习.
得: after verbs (complements), e.g., 说得很好.
In this sentence, only 的 is correct.

Can 的 be omitted after color words?

Often yes. Options (all natural):

蓝衣服 / 红衣服
蓝色衣服 / 红色衣服
蓝色的衣服 / 红色的衣服
Using 的 can sound a bit more formal or explicit; omitting it is common in speech.

Could I just say 他觉得蓝色的衣服比红色的更合适 (without 穿)?

Yes. That shifts the focus slightly from the action “wearing” to the clothes themselves being more suitable (for him/for the occasion). Both versions are idiomatic.

Why use 觉得 and not 认为 or 想?

觉得: subjective feeling/opinion; very common in speech.
认为: more formal, reasoned judgment (writing/news).
想: to want/plan; also “to think” in the sense of “consider,” but not used for stating an opinion about a fact here.
So 他觉得… is the most natural choice.

Is 合适 the same as 适合? How do I choose?

They’re related but different in grammar:

合适: adjective. Use as a predicate: 这件衣服很合适。
适合: verb. Must take an object it suits: 这件衣服适合他/这个场合。
In this sentence, 更合适 fits because no explicit object is given. If you want to specify, say: 他觉得穿蓝色的衣服更适合他/这个场合。

Do I need 很 before 合适?

Not in comparisons. With plain adjectives as predicates, Chinese often adds a degree adverb like 很 (e.g., 很合适) to avoid sounding contrastive. But with 更/最/比较 or 比, you don’t add 很.

Is 穿 the right verb for “wear”? What about 戴?

穿: clothes, pants, shoes, socks (items you put your body into).
戴: accessories (hat, glasses, jewelry).
So 穿…衣服 is correct here.

Can I use 比较 instead of 比?

Don’t replace 比 with 比较 in the A-B comparison.

比较 is an adverb meaning “relatively/rather”: 穿蓝色的衣服比较合适 (“Wearing blue is relatively suitable”).
You can’t say A 比较 B… to mean “A is more than B.”

How can I make the comparison stronger or softer?

Stronger: A 比 B 合适多了/得多; you can also combine with 更: A 比 B 更合适多了.
Softer: A 比 B 稍微/有点儿合适 (spoken: 稍微 is better).
Add a reason: …更合适，因为…

Where do I put the person or occasion that something is suitable for?

Two common ways:

With 合适 (adjective): 对他/对这个场合来说，穿蓝色的衣服更合适。
With 适合 (verb): 穿蓝色的衣服更适合他/这个场合。

Why is there no “to be” (is) before 合适?

Chinese adjectives can function as predicates without a copula. 合适 itself serves as “is suitable.” The comparison marker (比/更) supplies the degree.

Pronunciation tips for this sentence?

觉得: juéde (the second syllable de is neutral tone).
衣服: yīfu (second syllable neutral).
更: gèng (fourth tone).
合适: héshì (2nd + 4th).

Is the “de” in 觉得 the same as 的?

No. In 觉得, de is just the second syllable of the verb; it’s not the particle 的. They’re pronounced the same but function differently.

Any other natural rephrasings?

他觉得穿蓝色的衣服比穿红色的衣服合适多了。 (much more suitable)
跟穿红色的衣服比，穿蓝色的衣服更合适。 (fronted comparison)
Opposite meaning: 他觉得穿蓝色的衣服不如穿红色的衣服合适。 / 穿蓝色的衣服没有穿红色的那么合适。