Learn Hardcore Chinese: tā xué zhōngwén xué le liǎng nián le, chéngjì yǐjīng hěn hǎo le. - She has studied Chinese for two years, and her grades are already very good.

学中文 is a verb–object phrase (V = 学, O = 中文).
When you add a duration (like 两年) to such verbs, Chinese often:
- repeats the verb, and
- puts the duration after the second verb.

So the pattern is:

她学中文学了两年了。
S + V + O + V + 了 + duration + 了

You can also say:

她学了两年中文了。

Both are correct. The version with repetition (学中文学了两年了) slightly emphasizes the activity of learning Chinese, while 学了两年中文了 can sound a bit more compact and natural in everyday speech.

她学中文两年了 is understandable but feels incomplete/unnatural; Chinese usually needs 了 and often repeats the verb or moves 中文 after the duration.

There are so many 了: 学了, 两年了, 很好了. What does each 了 do?

Each 了 has its own function.

学了
- This 了 is aspect 了, attached to the verb.
- It marks that the action of learning has been completed up to now for some time.
- With a duration, it contributes to the meaning “has been learning (for X time)”.
两年了 (end of first clause)
- This 了 is sentence-final 了 (often called change-of-state 了).
- Here it shows that up till now, the situation is: she has already learned Chinese for two years.
- It suggests the action is still ongoing.
Pattern: V 了 duration 了 often = “has been V‑ing for X (and still is)”.
很好了 (end of second clause)
- This 了 is also sentence-final 了.
- It indicates a new or changed situation: her grades are now very good, compared to before.
- It often implies improvement: they used not to be so good, now they are.

So:

学了 = grammatical aspect (how the action unfolds).
The two final 了 = “as of now” / new situation.

Can I drop one of the 了 in 学了两年了? What changes if I say 学了两年 or 学两年了?

These three are different:

学了两年了
- Standard pattern for “has been learning for two years (and is still learning)”.
- First 了 = aspect, second 了 = up-to-now / new situation.
学了两年 (no final 了)
- Usually understood as a completed period in the past.
- Often implies she is not learning anymore.
- Like “She studied for two years” (finished).
学两年了 (no first 了)
- Colloquially, many people still say this, and it can be understood as “has been learning for two years”.
- But in careful grammar, the most typical pattern is V 了 duration 了.
- Leaving out the first 了 is more informal and can sound a bit less standard.

For learners, the safest for “has been doing for X (and still is)” is:

学了两年了
or full clause: 她学中文学了两年了。

Why is there another 了 at the end: 成绩已经很好了? Isn’t 已经 enough to show “already”?

已经 and 了 do related but different jobs.

已经 (“already”) emphasizes time / extent: something has already reached a certain point.
Sentence-final 了 emphasizes state change: a new situation now exists.

In 成绩已经很好了:

已经 = Her grades have already become good (sooner or earlier than might be expected).
了 = Her grades are now good; this is a new situation compared with before.

If you drop 了 and say:

成绩已经很好。

it is grammatically fine, meaning “her grades are already very good,” but it sounds more neutral/descriptive.

With 了, it feels more like: “Now (after some time/effort), her grades are finally very good.”

Could I say 成绩很好了已经 instead of 成绩已经很好了?

In modern standard Mandarin:

The normal position for 已经 is before the verb or adjective phrase:
- 已经很好了
- 已经学了两年了

成绩很好了已经 is possible in very colloquial speech, especially with certain intonation, but:

It sounds informal and sometimes a bit dialectal.
For learners and in writing, you should stick to 成绩已经很好了.

Why do we need 很 in 很好了? Can’t we just say 成绩已经好了?

With adjectives like 好, 大, 高, etc., Chinese often uses 很 in simple predicative sentences:

成绩很好。 = Her grades are (very) good.

Here, 很 is often not strongly “very”, but a kind of default linker between subject and adjective: “is good”.

If you say:

成绩已经好了。

this is grammatically possible, but it usually means “Her grades have gotten better / are okay now” rather than “very good”. It focuses on improvement from bad → not bad anymore, not necessarily high level.

So:

成绩已经好了 ≈ “Her grades are okay now / have improved.”
成绩已经很好了 ≈ “Her grades are already very good now” (and likely much better than before).

How would I say “She studied Chinese for two years, but now she doesn’t study it anymore”?

To clearly show the action has stopped, you usually:

use 了 without the final ongoing 了, and
add something indicating no longer.

For example:

她学了两年中文，后来就没学了。
She studied Chinese for two years, then (after that) didn’t study anymore.
她学了两年中文，现在不学了。
She studied Chinese for two years; now she doesn’t study (it) anymore.

Compare:

她学中文学了两年了。
⇒ “She has been learning Chinese for two years (and is still learning).”

What’s the difference between 她学中文学了两年了 and 她已经学了两年中文了?

Both mean roughly “She has been learning Chinese for two years (and is still learning).”

Differences:

她学中文学了两年了
- Uses verb–object separation: V+O, then V again.
- Feels slightly more textbook / explicit about the structure.
- Emphasizes the activity of learning Chinese.
她已经学了两年中文了
- No verb repetition; 已经 highlights “already”.
- Feels very natural and common in conversation.
- Slightly more focus on the duration and the idea of “already that long”.

Both are correct. In everyday speech, you’ll hear 已经学了两年中文了 very often.

Why is it 两年, not 二年? What’s the difference between 两 and 二 here?

Both 两 (liǎng) and 二 (èr) mean “two”, but:

两 is normally used before measure words, including 年 (year as a time unit).
- 两年 = two years
- 两个学生 = two students
二 is used:
- in numbers (like 2, 20, 200), phone numbers, IDs, etc.
- in some fixed expressions (二楼, 二号, etc.)

So:

两年 ✓ natural
二年 ✗ generally not used in modern Mandarin

Could I say 她在学中文已经两年了 to mean “She has been learning Chinese for two years”?

Yes, that’s acceptable and natural:

她在学中文已经两年了。
她已经学中文两年了。

Notes:

在学中文 highlights the ongoing nature (is in the middle of learning).
The 已经 … 了 frame (已经 X 了) highlights “already (for this long)”.

Your original sentence 她学中文学了两年了 does not use 在, but the meaning “has been learning for two years and is still learning” is expressed through the V 了 duration 了 pattern.

What exactly does 成绩 mean here? Could we also say 她的中文已经很好了?

成绩 (chéngjì) usually means:

grades / results / marks (in school, exams, tests), or
more generally, achievements / performance.

In 成绩已经很好了, it probably means:

Her test scores / academic performance in Chinese are already very good.

If you say:

她的中文已经很好了。

you’re talking about her overall Chinese ability (speaking, understanding, etc.), not specifically her grades. Both sentences are natural but focus on slightly different things:

成绩已经很好了 = Tests and results are very good.
她的中文已经很好了 = Her Chinese itself is very good.

Why is there a comma between the two parts of the sentence? Are they two separate sentences?

The Chinese sentence:

她学中文学了两年了，成绩已经很好了。

is made of two clauses:

她学中文学了两年了
She has been learning Chinese for two years.
成绩已经很好了
Her grades are already very good now.

They are closely related (the second clause is a result or consequence of the first), so in Chinese it’s very natural to join them with a comma, rather than a conjunction like “so” or “therefore”.

You could also make this relationship explicit:

她学中文学了两年了，所以成绩已经很好了。
She has studied Chinese for two years, so her grades are already very good.

So they are separate clauses, often written as one sentence with a comma.