Learn Hardcore Chinese: tā zhīsuǒyǐ duì lìshǐ yǒu xìngqù, shì yīnwèi yéye chángcháng gěi tā jiǎng gùshi. - The reason she’s interested in history is that her grandpa often tells her stories.

之 here is a classical particle meaning “that” (as in “the thing that / the reason that”).
所以 here means “reason” or “cause” (related to the modern word 理由 “reason”).

Together, 之所以 doesn’t just mean “therefore” (like 所以 often does in modern Chinese). In this pattern it points forward to the reason that will be given after 是因为.

So:

她之所以对历史有兴趣 = “The reason she is interested in history…”
是因为爷爷常常给她讲故事 = “…is that her grandfather often told her stories.”

You could say simply:

她对历史有兴趣，因为爷爷常常给她讲故事。
That’s fine and more neutral. Using 之所以……是因为…… adds emphasis and makes it sound more explanatory or formal, like you are explicitly laying out cause and effect.

How does the whole pattern “之所以……，是因为……” work? Can I change its order or leave parts out?

The basic structure is:

A 之所以 + [result / situation]，是因为 B + [reason]。
The reason why A is the case is because B.

In this sentence:

A = 她
Result/situation = 对历史有兴趣
B = 爷爷常常给她讲故事

So the structure is:

她之所以对历史有兴趣，是因为爷爷常常给她讲故事。

About flexibility:

Can you omit 是?
- Yes, often in speech/writing you’ll see:
  - 她之所以对历史有兴趣，是因为爷爷常常给她讲故事。
  - 她之所以对历史有兴趣，因为爷爷常常给她讲故事。
    Both are acceptable; 是 just makes the structure clearer and a bit more formal.
Can you omit 因为?
- In this fixed pattern, usually 因为 is kept. If you drop 因为, it sounds incomplete or too literary in modern usage:
  - ✗ 她之所以对历史有兴趣，是爷爷常常给她讲故事。 (not natural in standard modern style)
Can you reverse the order?
- Not with 之所以……是因为……; that pattern is directional and normally not reversed.
- But you can say the same idea in a simpler causal order:
  - 因为爷爷常常给她讲故事，她对历史有兴趣。

What is the function of 对 in 对历史有兴趣?

对 (duì) here is a preposition meaning roughly “towards / regarding / with respect to”.

The pattern is:

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

So:

对历史有兴趣 = “to have interest in history”
对音乐感兴趣 = “to be interested in music”

In English we use the preposition “in”; in Chinese this is usually 对 in this expression.

You can’t say:

✗ 她在历史有兴趣 (wrong)
✗ 她对历史是有兴趣 (the 是 is not needed here and sounds wrong in neutral description)

Why is it 对历史有兴趣 and not something like 对历史兴趣有 or 对历史是有兴趣的?

The natural and standard pattern is:

对 + object + 有兴趣 / 没兴趣

where 有 / 没有 works as the verb (“to have / not have”), and 兴趣 is the object of 有. The whole prepositional phrase 对历史 describes where that interest is directed.

So the internal structure is:

(对历史) = prepositional phrase
有 = verb “have”
兴趣 = noun “interest”

✗ 对历史兴趣有 is wrong because in Chinese you don’t normally put the object (兴趣) before the verb (有) in this way.

You do sometimes see:

对历史是很有兴趣的
This is more emphatic or descriptive, using 是……的 as a structure to highlight the state:
literally “As for history, (she) really does have interest.”
But that’s stylistically different; the basic, most common pattern is just 对历史有兴趣.

What’s the difference between 有兴趣 and 感兴趣? Can I say 对历史感兴趣 instead?

Both are common and correct, and both translate to “to be interested in”.

有兴趣 = “to have interest” (noun phrase 兴趣, verb 有)
感兴趣 = “to feel interested” (verb phrase with 感 “to feel”)

Patterns:

对历史有兴趣
对历史很感兴趣
Both are fine.

Subtle differences:

感兴趣 is slightly more “feeling-oriented” and often appears with 很 / 非常:
- 他对中国文化很感兴趣。
有兴趣 can sound a bit more neutral or objective, but in many contexts they’re interchangeable.

You generally cannot say:

✗ 她有对历史兴趣。 (wrong order)
Stick with 对历史有兴趣 or 对历史(很)感兴趣.

Why is there no 很 before 有兴趣? Would 她对历史很有兴趣 be okay?

Both are possible, but slightly different in feel.

Without 很:
- 她对历史有兴趣。
- Simply states a fact: “She is (at least somewhat) interested in history.”
With 很:
- 她对历史很有兴趣。
- Adds emphasis: “She is very/really interested in history.”

In neutral descriptions with stative verbs/adjectives, Chinese often inserts 很 even when English doesn’t say “very”, but with 有兴趣, 很 is more genuinely emphatic than “dummy”. So:

Here, the sentence is explaining the reason she is interested; it’s natural to just say 有兴趣 without adding degree.

What does 给 do in 爷爷常常给她讲故事? Could we say 爷爷常常讲故事给她 instead?

给 (gěi) here is a coverb/preposition meaning “to / for (someone)”, marking the indirect object (the person receiving the action).

Structure:

爷爷 (subject)
常常 (adverb, “often”)
给她 (prepositional phrase: “to her”)
讲故事 (verb-object: “tell stories”)

So 给她 = “to her”.

About word order:

爷爷常常给她讲故事。
- Very natural. “Grandpa often tells stories to her.”
爷爷常常讲故事给她。
- Also possible, but sounds less neutral and can be awkward in some contexts; it may feel like you’re focusing on “stories” as a unit being given.
- With pronouns, the 给她-before-verb pattern is far more common.

Colloquially, the given sentence is the most natural version.

Why is it 讲故事 and not just 讲? Is 故事 required?

讲故事 is a verb-object phrase: 讲 (tell) + 故事 (story).

讲 by itself just means “to speak / to talk / to tell”. It usually needs an object to be specific.
讲故事 specifies what is being told: “tell stories”.

In context:

爷爷常常给她讲。 feels incomplete: “Grandpa often tells her (something)” — the object is missing. You’d only drop 故事 if the context already makes the object crystal clear and very recent, or if it’s a deliberate ellipsis in dialogue.

So in a self-contained sentence like this, 讲故事 is the natural and complete expression.

Why isn’t there a 了 after 讲? Why not 爷爷常常给她讲了故事?

常常 describes a habitual / repeated action, not a single completed event.

常常给她讲故事 = “often tells her stories” (habit)
讲了故事 usually marks a completed event (“told (a) story”)

Putting 常常 (often) together with 了 (past/completion marker) on the same verb is usually odd: one says “habit” and the other says “one completed event”. So:

✗ 爷爷常常给她讲了故事。 is ungrammatical or at least very unnatural.

If you want to use 了, you would normally describe one time:

昨天爷爷给她讲了一个故事。 – “Yesterday Grandpa told her a story.”

Why is the subject 她 repeated? Could we say 她之所以对历史有兴趣，是因为爷爷常常给讲故事。?

You normally need the object 她 after 给 here.

The two 她’s have different roles:

First 她 = subject of the whole sentence.
Second 她 = indirect object of 给 (“to her”).

Omitting the object after 给 makes the sentence sound incomplete:

✗ 爷爷常常给讲故事。 = “Grandpa often gives tell stories.” — to whom?

Chinese often allows dropping subjects and objects when they are clear from context, but in a single sentence with no prior context, including 她 the second time is the standard, clear form.

In a conversation, if it’s completely obvious who is being told the stories, people might say 爷爷常常给我讲故事 → later shorten to 常常给我讲故事 once 爷爷 is known, but 给谁 is usually kept.

Why is it just 爷爷, not 她的爷爷 or 我爷爷? How do we know whose grandfather it is?

Chinese often omits possessive pronouns (的) when the relationship is clear or obvious. Family members are a typical case.

In context, we’re talking about 她 (she), so the default assumption is that 爷爷 is her grandfather. Saying 她的爷爷 is acceptable but slightly heavier:

她之所以对历史有兴趣，是因为她的爷爷常常给她讲故事。
This is grammatically fine but repeats 她 three times; Chinese usually likes to avoid that kind of redundancy when it’s clear from context.

So:

爷爷 alone is natural when the possessor is obvious.

Can I simplify the sentence and still keep the same meaning?

Yes. Several simpler but natural versions:

Drop the 之所以……是因为 pattern and just use 因为–所以 or simple 因为:
- 因为爷爷常常给她讲故事，她对历史有兴趣。
- 她对历史有兴趣，因为爷爷常常给她讲故事。
Use 感兴趣 instead of 有兴趣:
- 她对历史很感兴趣，因为爷爷常常给她讲故事。

All of these keep the core meaning: her interest in history comes from her grandfather often telling her stories. The original version with 之所以……是因为…… is just more explicitly explanatory and slightly more formal.