sono kouen ha yuugu ga ooi node, kodomotati ha nagai zikan asobemasu.

This is a very common pattern in Japanese.

• 公園は sets the overall topic: As for that park...
• 遊具が多い says what is true about that park: it has many playground structures/equipment

So the sentence is structured like:

• その公園は = speaking about that park
• 遊具が多い = the playground equipment is numerous

In other words, は marks the big topic, while が marks the thing being described within that topic.

A very literal breakdown would be:

• As for that park, playground equipment is plentiful, so...

This kind of は ... が ... pattern is extremely common in Japanese.

Japanese often expresses having a lot of something with the pattern:

• Noun が 多い = there is a lot of N / N is numerous

So:

• 遊具が多い = there is a lot of playground equipment

Japanese does have verbs like ある and いる for existence, but 多い is the natural way to say that something exists in large quantity.

Compare:

• 遊具がある = there is playground equipment
• 遊具が多い = there is a lot of playground equipment

So 多い is not exactly have; it is more like be many / be numerous.

遊具 usually means playground equipment or play equipment.

In the context of a park, it refers to things like:

• swings
• slides
• jungle gyms
• climbing frames
• seesaws

So 遊具が多い means the park has many things for children to play on.

Both ので and から can mean because / so, but the nuance is a little different.

• ので sounds a bit softer, more explanatory, and slightly more formal
• から can sound more direct or more personal

So:

• 遊具が多いので、子供たちは長い時間遊べます。 = Because there is a lot of playground equipment, children can play for a long time.

This sounds like a calm explanation.

If you said:

• 遊具が多いから、子供たちは長い時間遊べます。

that would also be correct, but it feels a little more conversational and direct.

遊べます is the potential form of 遊ぶ, so it means:

• can play

Meanwhile:

• 遊びます = play / will play
• 遊べます = can play / are able to play

The sentence is not just saying that the children play for a long time. It is saying that, because there is a lot of equipment, they are able to play for a long time.

So the potential form is important here.

The dictionary form is 遊ぶ.

This is a u-verb. To make the potential form:

• change the final u sound to the corresponding e sound
• then add る

So:

• 遊ぶ → 遊べる

Then make it polite:

• 遊べる → 遊べます

So:

• 遊ぶ = to play
• 遊べる = can play
• 遊べます = can play (polite)

長い時間 is a set phrase meaning:

• a long time
• for a long time

Here, 長い directly modifies 時間, just like an adjective before a noun in English:

• long time

By contrast, 長く is the adverb form of 長い, so it modifies verbs or adjectives, not nouns.

Compare:

• 長い時間 = a long time
• 長く遊べます = can play for a long time

Both of these are natural:

• 長い時間遊べます
• 長く遊べます

The sentence uses the noun phrase 長い時間.

Here, 子供たちは marks children as the topic of the second part of the sentence.

The structure is roughly:

• As for that park, because there is a lot of playground equipment, as for the children, they can play for a long time.

In natural English we would not repeat topics this way, but Japanese often does.

So:

• その公園は = as for that park
• 子供たちは = as for the children

This helps organize the information clearly:

1. talk about the park
2. explain its condition
3. state what is true for the children there

たち is a common plural-like marker for people.

• 子供 = child / children, depending on context
• 子供たち = children

Japanese nouns usually do not have to show singular vs. plural as clearly as English does, so 子供 by itself could already mean children in context.

Adding たち makes the plural idea clearer and often sounds a bit more specific.

So:

• 子供は遊べます = children/a child can play
• 子供たちは遊べます = the children can play

It is not always strictly required, but it is very natural here.

It means can play for a long time.

Japanese often omits words that English requires, especially prepositions like for. So:

• 長い時間 = a long time
• 長い時間遊べます = can play for a long time

The meaning of for is understood from the grammar and context.

Yes, depending on context.

• その公園 = that park
• 公園 = park / the park / a park, depending on context

Using その shows that the speaker is referring to a specific park that has already been mentioned or is known to both speaker and listener.

So その is used when the park is identifiable:

• maybe you were already talking about it
• maybe both people know which park it is

Without その, the sentence would feel more general or less specifically tied to a previously mentioned park.

Japanese normally does not use spaces between words in ordinary writing.

The sentence would usually be written like this:

その公園は遊具が多いので、子供たちは長い時間遊べます。

Spaces are often added in beginner materials to make it easier to see the parts of the sentence.

So the spaced version is for learning, not standard native writing.