tā juéde zìjǐ de fángjiān jì xiǎo yòu shūfu.

In modern Chinese, when an adjective is directly used as a predicate (describing the subject), you usually do not use 是.

So:

• 房间小。 = The room is small.
• 房间很小。 = The room is (very) small.
  You normally only use 是 before nouns, not simple adjectives:
• 他是老师。 = He is a teacher.

That is why the sentence is 房间既小又舒服, not 房间是既小又舒服.

The pattern 既 A 又 B already links two adjectives, so you don’t insert 很 inside that structure.

You could say:

• 房间既很小又很舒服。 (grammatically okay, but sounds a bit heavy or emphatic)
  In everyday speech, Chinese speakers prefer the shorter 既小又舒服. The 既…又… pattern itself is enough to make it sound like a natural, complete description.

Literally, 既…又… means both … and …. It is structurally an AND, not a BUT.

However, the two qualities often contrast in a way that feels a bit surprising or noteworthy, so in natural English we might translate it as:

• His room is small but comfortable.

Grammatically, though, it is not a contrastive but word. It simply lists two coexisting features of the same thing.

You can use 既…又… with adjectives and with verbs.

Examples with adjectives:

• 既小又舒服 – both small and comfortable
• 既便宜又好看 – both cheap and good‑looking

Examples with verbs:

• 他既工作又学习。 – He both works and studies.
• 她既会说英语又会说汉语。 – She can speak both English and Chinese.

The structure is: subject + 既 + element 1 + 又 + element 2, where each element is parallel (both verbs, or both adjectives, etc.).

又…又… and 既…又… are very similar; both can mean both … and ….

• 又…又… feels a bit more colloquial and is extremely common.
• 既…又… can feel a little more formal or bookish, though it is also used in speech.

For this sentence, you could say:

• 房间又小又舒服。 – perfectly natural and very common.
  The meaning is basically the same as 既小又舒服.

和 connects nouns most naturally (person A 和 person B; apples and bananas). It can link adjectives in a noun phrase (e.g. 小和舒服的房间), but it is not used to make the predicate pattern you see here.

The fixed structure is 既…又… (or 又…又…) for both A and B as qualities of the subject.
So:

• 房间既小又舒服。 ✅
• 房间既小和舒服。 ❌ (unnatural / incorrect)

觉得 mainly expresses a subjective feeling or impression:

• 他觉得房间小。 – He feels / thinks (in his opinion) the room is small.

认为 is more formal and often sounds like a considered judgment or opinion, sometimes based on reasoning or facts:

• 专家认为这个方法很有效。 – Experts believe / hold the view that this method is effective.

想 often means to think = to consider / to have in mind / to want:

• 我想他今天不会来。 – I think he won’t come today.
• 我想去中国。 – I want to go to China.

In this sentence, 觉得 is ideal because he is just giving his personal, subjective feeling about his room.

In 他觉得自己的房间…, 自己 is a reflexive pronoun meaning self / oneself.

In simple sentences, 自己 usually refers to the subject of the clause. Here, the subject is 他, so 自己 means himself → his own room.

In more complex sentences with multiple possible referents, 自己 can sometimes be ambiguous, and context decides who it refers to. But in this sentence, the natural interpretation is his own.

Here, 自己 is used as a possessive, so we treat 自己 like 他 or 我 and put 的 after it:

• 自己的房间 – one’s own room
• 他的房间 – his room
• 我的房间 – my room

他觉得自己房间既小又舒服 (without 的) can sometimes appear in fast speech or informal writing, but the standard, clear form is 他觉得自己的房间…. With 的, it is unambiguously his own room, not himself, the room (which would be ungrammatical anyway).

No. Because 的房间 is there, 自己 is clearly modifying 房间:

• 自己的房间 = his own room

If you wanted to say He thinks he himself is small and (somehow) comfortable, you would need a different structure, for example:

• 他觉得自己又小又舒服。 (Even then it sounds odd in meaning; 小 and 舒服 are not typical properties of a person in that collocation.)

So in the original sentence, the only natural reading is about his room, not about himself.

No. 自己 cannot randomly float like that. It must fit into a grammatical role: subject, object, modifier, etc.

In 自己的房间, 自己 + 的 together form an adjective‑like modifier of 房间 (one’s own room). Moving 自己 to 房间自己 breaks that relationship and becomes ungrammatical here.

Correct options include:

• 他觉得自己的房间既小又舒服。
• 他觉得自己住的房间既小又舒服。 – He thinks the room he lives in is small but comfortable.

Yes, there is a nuance:

• 自己的房间 (in this sentence) already refers back to the subject 他, so it naturally means his own room.
• 他自己的房间 adds 他, making it more explicit and sometimes more emphatic: his own room (as opposed to someone else’s).

For example, in a context with several people:

• 他不喜欢住别人的房间，他只喜欢住他自己的房间。
  – He doesn’t like staying in other people’s rooms; he only likes staying in his own room.

You can say 既小又舒适; it is correct.

Nuance:

• 舒服 is more colloquial and very common in everyday speech.
• 舒适 sounds a bit more formal or written, and is often used in descriptions (e.g. hotel ads, product descriptions).

For speaking about your own room, 舒服 is more natural and conversational:

• 房间虽然小，但是很舒服。 – The room is small, but (it feels) very comfortable.

Yes. Chinese is a pro‑drop language: subjects (and sometimes objects) can be left out if they are obvious from context.

If your listeners already know you are talking about him, you could say simply:

• 觉得自己的房间既小又舒服。

The full form with 他 is clearer in an isolated sentence or in writing, but omitting it is very natural in ongoing conversation.