Learn Hardcore Chinese: yǒude xuéshēng xǐhuan zài gōngyuán sànbù, yǒude xuéshēng xǐhuan zài jiā shàngwǎng. - Some students like to take a walk in the park; some students like to go online at home.

有的…有的… is a very standard, natural pattern for “some …, some …”.
一些学生 …，另一些学生 … sounds a bit more formal / written and emphasizes two definite subgroups (“some students…, the other some students…”).

For everyday speech and simple writing, 有的学生……，有的学生…… is more common.

Why isn’t there a plural marker 们 after 学生? Why not 学生们?

Chinese usually does not mark plural on nouns like English does.

学生 can mean “student” or “students”, depending on context.
们 is mostly used after pronouns (我们，你们，他们) or specific, definite people (e.g. 同学们, “you students / classmates” when calling out to a group).

Here we’re talking about students in general, as a category, not a specific group that we’re addressing directly, so 学生 without 们 is natural and normal:

有的学生喜欢… = “Some students like …”

What is the basic structure of 在公园散步? Why is the place word before the action?

The pattern is:

在 + 地点 (place) + 动作 (action)
“to do [action] at/in [place]”

So:

在公园散步 = “(to) take a walk in the park”
在家上网 = “(to) go online at home”

In Chinese, the location phrase (with 在) comes before the main action verb, not after it the way English often does. So:

在公园散步 (correct)
散步在公园 (sounds unnatural in modern Mandarin in this context)

Can I say 有的学生喜欢散步在公园 or 有的学生喜欢上网在家?

No, those orders are unnatural.

The usual order with 在 is:

在 + 地点 + 动词 / 动作

So the natural versions are:

有的学生喜欢在公园散步。
有的学生喜欢在家上网。

Putting 在 + place after the verb (散步在公园, 上网在家) is generally not used in this kind of sentence in modern Mandarin.

Why do we repeat 有的学生 in the second half? Can we shorten it?

The full sentence repeats it for balance:

有的学生喜欢在公园散步，有的学生喜欢在家上网。

But it is very natural (and common) to shorten it to:

有的学生喜欢在公园散步，有的喜欢在家上网。

Here, the second 有的 clearly still refers to 学生, so 学生 can be omitted.
You should keep the second 有的, though; if you drop it too, it breaks the “some …, some …” pattern.

Is 在 here a verb (“to be at”) or a preposition (“at / in”)?

In modern Chinese grammar, in this kind of sentence 在 is treated as a preposition meaning “at / in / on”:

在公园散步 – “walk in the park”
在家上网 – “go online at home”

Historically 在 comes from a verb meaning “to be (at a place)”, but for learners it’s easiest to think of it here as a preposition that introduces a location phrase.

What does 散步 literally mean, and how is it different from 走路?

散步 (sànbù) literally is “to scatter/spread + steps”, and it means “to take a walk / to stroll (for leisure or relaxation)”.
走路 (zǒu lù) literally “walk road”, and it means “to walk / to go on foot”, with no special idea of leisure.

So:

在公园散步 – “take a stroll in the park” (for enjoyment)
走路去学校 – “walk to school” (mode of transport)

In this sentence, 散步 fits better because it’s about what students like to do for fun.

What does 上网 mean literally? Why is 上 used?

上 (shàng) has meanings like “to go up / to get on / to attend / to go to”.
网 (wǎng) is “net / network”, in modern usage “the internet”.

So 上网 literally is “to get on the net(work)”, and it means:

“to go online / to use the internet / to surf the internet”

The same 上 is used in other expressions:

上班 – go to work
上学 – go to school
上课 – attend class

Why can 喜欢 be followed directly by another verb phrase without anything like “to”?

In Chinese, a verb like 喜欢 can be followed directly by a verb phrase without any extra word like English “to” or “-ing”:

喜欢吃饭 – “like to eat / like eating”
喜欢看书 – “like to read / like reading”
喜欢在公园散步 – “like to take walks in the park / like walking in the park”

So the structure is:

喜欢 + [在 + 地点 + 动作]

Chinese doesn’t need a separate infinitive marker (“to”) or gerund ending (“-ing”) here.

How is tense expressed here? How do we know this is about what they usually like, not the past?

Chinese verbs don’t change form for tense (no -ed / -s / -ing like English).
Tense and aspect are shown by:

Time words (以前, 现在, 明天, 常常, 每天, etc.)
Context
Aspect particles like 了, 过, 着 when needed

Here there is no explicit time word, so 喜欢在公园散步 / 喜欢在家上网 is understood as a general, timeless or habitual preference, which in English naturally becomes:

“Some students like …, some students like …”

Can I say 在公园里散步 instead of 在公园散步? Is there a difference?

Yes, both are correct:

在公园散步 – “take a walk in the park”
在公园里散步 – also “take a walk in the park”

Adding 里 emphasizes “inside” the park a bit more, but in practice the meaning is almost the same, and both sound natural. The version without 里 is a little shorter and very common.

Could I use 爱 instead of 喜欢 here, like 有的学生爱在公园散步?

You generally wouldn’t.

爱 is stronger and often used for love between people, strong affection, or very strong likes.
喜欢 is the normal word for “to like / to be fond of”, especially for hobbies and everyday preferences.

So:

有的学生喜欢在公园散步 – sounds natural.
有的学生爱在公园散步 – sounds a bit odd or too strong for a simple hobby statement.

Use 喜欢 for “like doing [activity]” in most cases.

How should I pronounce 学生 and 喜欢? I’ve seen different tones in speech.

Standard dictionary forms:

学 – xué, 2nd tone
生 – shēng, 1st tone → 学生 (xuéshēng)

In everyday speech, many speakers pronounce 生 here with a neutral tone: xuésheng. Both are accepted; the neutral tone version is very common in casual speech.

喜 – xǐ, 3rd tone
欢 – huan, usually neutral tone in 喜欢 → xǐhuan

So you say xǐhuan, not xǐhuān. The second syllable is light and unstressed.