Learn Hardcore Chinese: Xiànzài hěnduō rén zài wǎngshàng xué zhōngwén, cānjiā gèzhǒng zhōngwén kèchéng. - Nowadays many people study Chinese online and take all kinds of Chinese courses.

在 – “at / in / on” (preposition indicating location)
网 – “net; network” (here: the internet)
上 – “on, above; on top of; in” (used after a noun to make it into a location: on the X)

So 网上 literally means “on the net,” and 在网上 literally is “at on-the-net,” i.e. “on the internet / online.”

In practice:

网上 often appears alone as an adverbial:
- 网上购物 – “online shopping”
在网上 is very common when you explicitly mark location with 在:
- 在网上学中文 – “study Chinese online”

Using both 在 and 上 here is normal in Chinese: 在 + (place word) + 上 is a standard pattern (e.g. 在桌子上 – “on the table”).

Is the 在 in 在网上学中文 the same 在 as in the progressive aspect (like “be doing”)?

No. There are two common uses of 在:

Location marker – as in this sentence
- 在网上学中文 = “study Chinese on the internet”
  Here 在 introduces a location: “at / on.”
Progressive marker – “be doing … now”
- 在学中文 / 正在学中文 = “(am) studying Chinese (right now)”

In your sentence, 在 belongs with 网上 and forms a location phrase:

在网上 (location) + 学中文 (action)

If you wanted to emphasize the ongoing action and the location, you might say:

很多人正在网上学中文。
(“Many people are currently studying Chinese online.”)

Here 正(在) is the progressive marker, 在网上 is still the location.

Why does the sentence start with 现在? Is it necessary?

现在 means “now; nowadays; at present” and sets the time frame:

现在很多人在网上学中文
= “Nowadays, many people study Chinese online.”

Is it necessary?
Grammatically no, you can drop it:

很多人在网上学中文。 – “Many people study Chinese online.”

But 现在 adds the idea that this is a current trend, contrasting with the past. Alternatives with similar meaning include 目前, 如今, 当今, but 现在 is the most common, neutral choice.

What is the nuance of 很多人? Is it “very many people” or just “many people”?

很多人 means “many people / a lot of people.”

很 here doesn’t really mean “very” in the strong English sense; with 多, it usually just makes it sound natural and smooth.
You can also say 许多人 or 很多的人 (rare in speech), but 很多人 is by far the most common in conversation.

So read 很多人 simply as “many people,” not “extremely many people.”

Can I change the word order to 在网上很多人学中文?

Yes, you can say 在网上很多人学中文, and it is grammatically correct. The nuance:

很多人在网上学中文
– neutral, focusing first on many people and then telling you where they study.
在网上很多人学中文
– starts by highlighting the place (online), then saying that many people study Chinese there.

Both are fine; the original is the more typical, neutral word order.

What is the difference between 学中文 and 学习中文?

Both 学中文 and 学习中文 mean “study/learn Chinese.”

学 – shorter, more colloquial, very common in speech
- 我学中文。 – “I study Chinese.”
学习 – slightly more formal or “complete,” often used in written language or more formal contexts
- 我在学校学习中文。 – “I study Chinese at school.”

In everyday speech, 学中文 is perfectly natural and often preferred. Using 学习中文 here would also be correct but sounds a bit more formal or bookish.

Why is 中文 used here? Could we say 汉语 or 普通话 instead?

All three relate to the Chinese language, but with different common uses:

中文
- Broad: “Chinese (language),” often including reading and writing.
- Common in course names, online learning, apps, etc.
- Works well in “study Chinese” in a general sense.
汉语
- Literally “the Han language,” i.e. the Chinese language.
- Often used in linguistics, foreign-language teaching, test names:
  - 对外汉语 – “Teaching Chinese as a foreign language.”
普通话
- Specifically “Mandarin” (the standard spoken variety in Mainland China).
- Focuses on the spoken standard, not writing or classical language.

In this sentence, 中文 is the most natural because online courses usually teach reading, writing, and standard modern Chinese as a whole. You could say 汉语课程, but 中文课程 is more common in many contexts, especially informal or commercial ones.

What does 参加 mean here, and how is it different from verbs like 上 or 修 with 课程?

参加 means “to participate in; to take part in; to attend.”
So:

参加各种中文课程 – “take part in various Chinese courses.”

Common alternatives with slightly different angles:

上中文课 / 上中文课程 – literally “attend Chinese class/course,” very common and colloquial.
修中文课 / 修中文课程 – “take a Chinese course” in the academic sense (more common in Taiwan and in formal/university settings).

Nuance:

参加课程 – emphasizes joining/participating.
上课 – “have class / attend class” (focuses on the act of attending lessons).
修课 – focus on “taking” the course for credit.

In this general statement about people taking online courses, 参加各种中文课程 is natural and idiomatic.

Why is there no measure word between 各种 and 中文课程? Should it be 各种中文课程 or 各种中文的课程 or 各种中文课程 with a classifier?

The phrase 各种中文课程 is already correct and natural. Breakdown:

各 – each
种 – kind / type
各种 – “all kinds of; various” (fixed phrase)

When 各种 directly modifies a noun, you usually do not insert an extra measure word:

各种书 – all kinds of books
各种问题 – various problems
各种中文课程 – various Chinese courses

You can also say 各种各样的中文课程, which is a bit more emphatic (“all sorts of Chinese courses”), but it’s longer and not necessary here.

What is the function of the comma between 学中文 and 参加各种中文课程? Is it like “and”?

Yes, the comma is linking two verbs that share the same subject (很多人):

很多人在网上学中文，参加各种中文课程。
→ “Many people study Chinese online and (also) take various Chinese courses.”

In Chinese, it’s common to chain actions like this:

他每天跑步、做饭、看书。
– “He runs, cooks, and reads every day.”

You could add 也 or 还 to make the “also” explicit:

现在很多人在网上学中文，也参加各种中文课程。
现在很多人在网上学中文，还参加各种中文课程。

But it’s not required; the simple comma already suggests an “and/also” relationship.

What does 各种 add here? Could we just say 中文课程?

各种 means “various; all kinds of,” so:

中文课程 – “Chinese courses” (neutral, no comment on variety).
各种中文课程 – “various Chinese courses / all kinds of Chinese courses.”

It suggests there is a range of different course types: beginner, advanced, speaking, reading, HSK prep, etc. It gives the idea of variety, which fits the context of online offerings.

What is the difference between 课程 and 课 in this context?

Both relate to classes / courses, but:

课
- Often means an individual class session or a subject:
  - 一节课 – one class period
  - 中文课 – Chinese class (subject or specific lesson)
课程
- More like “course; curriculum; program,” often more formal or structured:
  - 中文课程 – a Chinese course
  - 培训课程 – training course
  - 大学课程 – university courses

In 参加各种中文课程, 课程 emphasizes organized courses or programs, which fits the idea of online course offerings. Saying 参加各种中文课 is understandable but sounds a bit less formal.

Could I use 网上 alone as an adverb, like 很多人网上学中文 without 在?

In practice, 很多人网上学中文 (without 在) is possible and some native speakers do say or write things like this, treating 网上 almost like an adverb.

However, 在网上学中文 is:

more standard
clearer for learners
extremely common and natural

So you should prefer 在网上学中文. Using 网上 alone like that is more colloquial and not the best form to learn first.

Is 在网上学中文 the only way to say “study Chinese online”? What about 在线学中文 or 网上学中文?

There are several natural options, with slightly different flavors:

在网上学中文
- Very common, neutral: “study Chinese on the internet / online.”
网上学中文
- Also common, especially in short phrases/headlines; 在 is sometimes omitted in casual usage.
在线学中文
- 在线 = “online (online-status/adjective)”; sounds a bit more technical/modern, common in marketing or web UI:
  - 在线学中文，随时随地！ – “Learn Chinese online, anytime, anywhere!”

All are understandable. For a general sentence like this, 在网上学中文 is a great default.