Same as other countries, an era of ageing era is approaching to China.

"ageing era" sounds like the era itself is what is ageing

However, China also has its exclusiveown problems.

"exclusive" means "limited, single, undivided", and it doesn't really sound correct the way you used it.

https://www.merriam-webster.com/dictionary/exclusive

In the fast-paced society of China, elderly people tend to live alone, not spontaneouslyby choice but forcedly.

"spontaneously" doesn't sound right here, because it means "all of a sudden, all at once". You use it to describe something that happens very quickly without being planned.

https://www.merriam-webster.com/dictionary/spontaneously

And the reasons are as followed, f: First of all, on accountbecause of the thChinese traditional method of China— yang er fang lao, i.e, (raising children for the sake of the old age), many Chinese parents endeavour to rearaise their children and provide as best condition as they can for children to build up their own lifethem the best lives they can, and leave scarcehardly any savings for themselves.

Okay, I changed a couple of things here.

In the first sentence, you typically put a colon after the phrase "as follows", rather than a comma

I don't see a way to put words in italics, but usually when you are writing in English and you introduce a foreign word or phrase, such as yang er fang lao, you write it in italics. https://www.dailywritingtips.com/italicizing-foreign-words/

"rear" is normally used when talking about taking care of animals. when you talk about taking care of children, use "raise", instead.

The last sentence was a run on so I shortened it up

In that case, hHere comes the second question, their offsprings have to go to the metropolitan where isproblem: their children have to go to the city far from home in order to searching for work.

"offspring" is normally used when talking about animals, we don't normally use it to talk about human children

"metropolitan" is an adjective so you wouldn't use it as a noun like you did. I replaced it with "city"

Since it isn’t easy to take seniors with them even they eager to, ough they want to go, those elderly people have to stay solelyhome alone, which is even more solitary for them when their significant other has passed away.

"eager to" isn't the full phrase, you have to put a verb at the end. e.g., eager to go, eager to play, eager to work, etc.

"solely" is an adverb, and it doesn't sound natural the way you used it. I replaced it with "stay home alone"

Worse still, provisions are absolutely lagging behind in China, for the government assumes offspringschildren will no doubt to take the responsibility of caring for the old and sick.

You need to use the gerund form of a verb if you use it with is/are
The gerund form takes "-ing" at the end

Examples

Provisions are lagging behind in China
The children are playing baseball
I am writing corrections on LangCorrect

Same thing with "offspring" as before, we use that for talking about animals

And here are some measures that could be taken account of used.

Firstly and the most crucial thing is to establish a more maturreasonable policy on pension and retirement income.

"mature" doesn't really sound natural here

For instance, to aidwe can help people over 65 years old havinge sufficient living expenses every month, and to add thoswe should add people who isare approaching retirement into the list of people being helped, in particular people who live alone for particular.

Secondly, the neighbouring service also need to be refined.

Not sure what you mean by "neighboring service".

The government entail tomust put money inton this.

Lastly, considering some seniors would regard not being reared byassisted by their children as an embarrassing thing and would refuse the help, the experts for comforting them are also needed.

To sum up, even though the structurpractice of letting offsprings raisechildren take care of their parents has worksed for thousands of years in China, the system is require tomust be rebuilt to help the left olds ,so that toelderly who get left behind. That way, we can provide a better life for the oelderly and to ease the guilty of the youth for their insufficient ability to renprovider a bright later life tofor their parents.

This was a run-on sentence, so I cut it into two smaller sentences.
https://www.thoughtco.com/run-on-sentence-grammar-and-usage-1692069

In the first sentence, you are talking about something that started in the past, and continues to take place now, so you need the present perfect here. https://learnenglish.britishcouncil.org/grammar/intermediate-to-upper-intermediate/present-perfect-simple-and-continuous

When we talk about old people, usually we use the word "elderly" (which is plural). We don't call them the olds. The singular form is "elderly person"

instead of insufficient ability" you can just say "inability"