Why is 很多 sometimes before the noun and sometimes after the noun?

Question

I have sometimes seen 很多 after the noun and sometimes before and I don't understand what the reason is for it being in different places.

For instance, here it follows the noun, "活动":

中国的居民社区的休闲活动很多 There are many leisure activities in the residential communities of China.

However, in another sentence I've seen, it comes before the noun, "社区":

在中国，很多社区都有 老年大学 ，经常组织书法课堂活动。 In China, many communities have old people’s universities which often organize calligraphy classes.

Similarly, before the noun phrase, "退休的老年":

很多退休的老年居民都参加这个活动。Many retired elderly residents participate in this activity.

What is the reason for these various locations of 很多?

Answer 1

1. I actually generalised several rules on the placement of adjectives and adverbs in Chinese in an answer to a different question here. The numbered rules referred below correspond to the linked answer.

2. Your first sentence when simplified (居民活動很多。) evidently follows Rule 6:

   When a sentence states the quality of a noun, the adjective follows it (the noun).

   They don't follow the SVO structure; examples include 你好嗎？ and 他很高。. The adjective here is a semantically and syntactically essential component of the sentence; linguists call that comment. The first noun (居民) is what is called the topic, and the second noun (活動) the subject. Combined, the sentence means something like this: regarding the topic, the subject has the following comment from the speaker (here in the form of an adjective). Nothing else (e.g., no verbs). In your case, regarding residents, the speaker wishes to say that their activities are many. You can see more examples here.

3. Your second and third sentences both follow Rule 1:

   When 的 is used to attribute a quality to a noun, or indicate possession, the adjective always precedes the noun. The resulting phrase is nominal.

   In your second sentence, the nominal phrase is 很多社區. Note how semantically incomplete it is (as compared to a stand-alone sentence containing exactly the same noun and adjective, i.e., 社區很多。 lit. There are many communities.). Also, note how it is equivalent to 很多的社區 – 的 is omitted out of concision (Rule 3).

   You parsed the third sentence wrongly. 老年 is also adjectival (hidden 的) on 居民 here; in fact there are three adjectives that modify 居民. But Rules 1 and 3 again apply. Of course the order of which is another issue.

Answer 2

社区的休闲活动很多 is a [topic]+[comment] sentence

[社区的休闲活动] is the [topic]

[很多] is the [comment]

[社区的休闲活动][很多] = Community recreational activities are plenty

"很多社区的休闲活动" = "Many community recreational activities" (it is an incomplete sentence)

政府資助很多社区的休闲活动 = The government subsidizes recreational activities in many communities

It is a [svo] sentence. The adjective '很多' (many) is directly placed before the noun phrase 区的休闲活动 to modify it.

More example:

公園(是)很大的 = Parks are big - [Topic: 公園 + comment: (是)很大的]

很大的公園 = A big park [SVO]

公園很大 = (this) park is big - [Topic: (this) 公園 + comment: 很大]

Answer 3

What is the reason for these various locations of 很多?

The position of 很多 just depends on what you wish to talk about.

You can experiment, move 很多 around, see what you get! (Don't worry, nothing will explode!)

You want to say something about 活动:

活动很多。
Activities many
(There are) many activities.

You want to say something about 很多活动：

许多活动 ...
Many activities ...
许多活动都是在浪费时间和金钱。
Many activities are a waste of time and money.

You want to say something about 很多社区:

很多社区 ....
Many communities ...
很多社区都有 老年大学。 Many communities have (an) Old Folks Uni.
在中国，很多社区都有 老年大学。
In China, many communities have (an) Old Folks Uni.
在中国，很多社区都有 老年大学 ，经常组织书法课堂活动。
In China, many communities have (an) Old Folks Uni (and they) often organise calligraphy classes.

You want to say something about 老年居民:

老年居民很多。
elderly residents many
(There are) many elderly residents.

You want to say something about 很多老年居民：

很多老年居民 ....
Many elderly residents ...
很多老年居民都参加这个活动。
Many elderly residents participate in this activity.
很多退休的老年居民都参加这个活动。
Many retired elderly residents participate in this activity.

This is just the same in English:

There are many activities.
Many activities are fun.

Answer 4

in chinese,

很多 used as many(adj), should be placed before the noun.

like:

• 广场上有(很多人)。 subject + predicate + object
• (很多小区)都有公共卫生间。

but， when placing after some word, it's non-bussiness about noun.

often, we use 很多/许多 like：

• 你让我(学到了很多)。 (adv.)
• 他家里（孩子很多）。 although 孩子 means kids, noun. but 很多 here means not only a lot, but also a status or description.
• 广场上（人很多）。 a lot of people used as adverbial, to describe a status.