Learn Hardcore Chinese: tā xué zhōngwén bù shì wèile kǎoshì, érshì yīnwèi duì zhōngwén yǒu xìngqù. - He studies Chinese not for exams, but because he is interested in Chinese.

不是为了考试 literally: “is not for exams”
Grammatically, 是 links the subject and the complement of purpose:
- 他学中文 是 为了考试 = He studies Chinese for exams.
- Negated: 他学中文不是为了考试.

You can say 他学中文不为了考试, and people will understand you, but:

不是为了… sounds more natural and standard.
The pattern 不（是）…，而是… almost always includes 是, especially in careful speech or writing.

So 不是为了考试 is the most natural and idiomatic choice here.

What is the difference between 为了 and 因为 in this sentence? Why do we need both?

为了 and 因为 look similar to English “for” and “because”, but they play different roles:

为了 + noun / verb phrase
- Expresses purpose / goal / intention
- Example: 为了考试学中文 = study Chinese for the exam / in order to pass the exam
因为 + clause
- Expresses cause / reason
- Example: 因为对中文有兴趣学中文 = study Chinese because he is interested in Chinese

In the sentence:

不是为了考试 → “it is not for the purpose of exams”
而是因为对中文有兴趣 → “but rather because he is interested in Chinese”

So the contrast is between:

A goal-oriented motivation (for exams)
A reason-based / interest-based motivation (because of interest)

Using both highlights this contrast very clearly.

Why do we use 而是 and not 但是 or 可是? Aren’t they all “but”?

而是 is special: it almost always appears after a negation and introduces the corrected alternative.

Pattern:

不（是）A，而是B = not A, but rather B

但是 and 可是 are more general “but / however” conjunctions and do not by themselves imply correction of a previous option.

Compare:

他学中文不是为了考试，而是因为对中文有兴趣。
Not for exams, but rather because he’s interested. ✅ (correction of an assumption)
他学中文为了考试，但是他也对中文有兴趣。
He studies Chinese for exams, but he’s also interested in Chinese. ✅ (simple contrast, not correction)

So here we need 而是 because the sentence is rejecting one reason and replacing it with another.

Why is there no 他 in the second part 而是因为对中文有兴趣? Shouldn’t it be 而是因为他对中文有兴趣?

Chinese often omits repeated subjects when they are clear from context.

Full version would be:

他学中文不是为了考试，而是因为他对中文有兴趣。

But since the subject 他 is already clear from 他学中文, it is natural to drop it in the second clause:

而是因为对中文有兴趣。
“…but rather because (he) is interested in Chinese.”

Both versions are grammatically correct.
Including 他 sounds a bit more formal or emphatic; omitting it makes the sentence smoother and less repetitive.

What exactly does 对 do in 对中文有兴趣? Why can’t we just say 有中文兴趣?

对 (duì) here is a preposition meaning something like “towards / with regard to / in relation to”.

The structure is:

对 + something + 有兴趣 = “to be interested in something”

So:

对中文有兴趣 = “have interest in Chinese / be interested in Chinese”

We don’t say 有中文兴趣 in normal Chinese; that sounds unnatural.
The standard patterns are:

对中文有兴趣
对中文很有兴趣 (very interested in Chinese)
对中文感兴趣 (be interested in Chinese)

Think of 对 as marking the object of interest, similar to “in” in English “interested in Chinese”.

Why do we say 有兴趣 and not just 兴趣? Is 兴趣 a noun or a verb here?

兴趣 (xìngqù) is a noun, meaning “interest”.

To say “to be interested in”, Chinese often uses the verb 有 (to have) with 兴趣:

有兴趣 = “have interest” → “be interested”

So:

对中文有兴趣 literally = “towards Chinese have interest” → “be interested in Chinese”

Common related patterns:

对中文有兴趣 = be interested in Chinese
对中文很有兴趣 = be very interested in Chinese
对中文感兴趣 = be interested in Chinese (using the verb 感兴趣, “to feel interest”)

Thus, 有 is necessary here because 兴趣 alone does not function as a verb.

Can we say 他不是为了考试学中文，而是因为对中文有兴趣? Does moving 学中文 change the meaning?

Yes, you can say:

他不是为了考试学中文，而是因为对中文有兴趣。

This is also correct and natural. The difference is nuance/emphasis:

他学中文不是为了考试，而是因为对中文有兴趣。
- Topic first: 他学中文 (as for his studying Chinese)
- Then we talk about why he does it.
- Feels like: “As for his studying Chinese, it’s not for exams, but because…”
他不是为了考试学中文，而是因为对中文有兴趣。
- The negation comes earlier.
- Slightly stronger emphasis on “it is not for exams that he studies Chinese”.

Both are fine in everyday speech. The original version is slightly smoother and very typical.

Why is it 不是 and not 没（有）是 or just 没? When do we use 不 vs 没 here?

不 (bù) and 没 (méi) are different negators:

不
- Negates present / future / habitual actions or states
- Used with 是: 不是 = “is not / are not / am not”
没 (有)
- Negates past actions, completion, possession
- Used with 有: 没有 = “do not have / did not”

Because 是 is a verb of identity / state, and we are negating a current fact about motivation (“it is not for exams”), we must use:

不是为了考试 = “is not for exams”

没（有）是为了考试 is ungrammatical in this kind of sentence.

Can we drop 因为 and just say 而是对中文有兴趣?

Yes, you can say:

他学中文不是为了考试，而是对中文有兴趣。

This is also common and correct.

Nuance:

而是对中文有兴趣
- Slightly more compact.
- Focuses on the state “(he) is interested in Chinese”.
而是因为对中文有兴趣
- Emphasizes that his interest is the reason.
- Feels a bit more explicit: “but rather because he is interested in Chinese.”

In everyday conversation, both versions are natural. Including 因为 just makes the causal connection more explicit.

What nuance does 为了考试 add compared to 因为考试?

为了考试 → for the sake of the exam / in order to pass exams
- Emphasizes purpose / goal
- Suggests he studies with the exam as a target.
因为考试 → because of the exam(s)
- Emphasizes reason / cause
- Sounds more like “He studies Chinese because there is an exam (or some exam pressure)”.

In this sentence, we’re contrasting:

Not studying as exam preparation (为了考试)
But studying out of interest (因为对中文有兴趣)

So 为了考试 is the most natural way to express that exam preparation is not his purpose.

Is 对中文有兴趣 the same as 对中文感兴趣? Which is more natural?

They are very close in meaning; both mean “be interested in Chinese”.

对中文有兴趣
- Literally: have interest in Chinese
- Slightly more noun-based (“has interest”)
- Very common and natural.
对中文感兴趣
- Literally: feel interest towards Chinese
- Slightly more verb-like (“feels interested”)
- Also extremely common.

In spoken Mandarin, both are fine and idiomatic:

他对中文很有兴趣。
他对中文很感兴趣。

Most learners can treat them as interchangeable in everyday use.

How should 不 be pronounced in 不是 in real speech? Is it bù shì or bú shì?

In careful dictionary form, 不 is bù (fourth tone).
But in real speech, 不 changes tone (tone sandhi) before another fourth tone:

Before 4th tone: 不 → bú (second tone)

是 (shì) is fourth tone, so:

不是 is pronounced bú shì in natural speech.

So you say: bú shì
Even though you write: 不是.