tTopic:

I think you meant to stylize this, but in places where you can't use stylistic fonts or art it is better to follow standard grammar rules.

In the developed world, average life expectancy ikeeps increasing.

This sound odd to me, but I can't explain why. You could also change it to "Average life expectancy is increasing in the developed world" if you want to preserve the original meaning.

Suggest some measures that could be taken to reduce the impact of ageing populations.

mMy taskanswer:

General life expectancy is longer than ever before in the developed counties.

"Ever before" makes it slightly more natural sounding here. Many essays also tend to have "ever before" instead of before in the opening line.

As the birth rate disecreasing, thees, countries will get intoenter an ageing society which has no benefit with the countriesfor them.

Encouraging more young couples to have more children and producing more intelligent robots would help to solve the ageing problem.

I would use "could" instead of "would" here, personally.

It is true that people can expect to live longer than ever before in developed countries.

Don't use "ever" here if you use it in the opening sentence. Also, this sentence is redundant and states something already said.

There will be various problems sucbsequent of the longer life expectancy, while there could be many methods to help with the influence of ageing populations.

This sentence is unclear. I don't understand what you were trying to say here.

Here are the disadvantages of the increasing expectancy for both citizens and the countries.:

For citizens, as people get older, it is possible that they will suffer from more diseases such as different types of cancers and heart attack.

For example, my grandmother died because of stomach cancer when she was 84 years old.

I watched she undergong a r go through a tremendous amount of pain in her last 3 years, but canould do nothing, which made me feel useless.

As for the society, the workforce ofn the whole society would be discrease as more experienced getwould decrease as more working people retired, meanwhile the birth rate is dropping in particularcontinues to drop.

Not sure what you meant by "in particular".

Young people would take on much more responsibility of their work and families, which may be more stressful for them.

In my opinion, there will be several ways to cope with the influenceeffects of ageing populations.

Firstly, governments should subsidisinge more families to have more children.

I think this line is redundant too.

Secondly, companies, especially IT technology companies can try to produce more intelligent robots to take care of the elder people.

IT = Information Technology, so technology would be redundant.

In conclusion, it could probably bhave many consequences as more people live a longer life in the developed countries, but there stwill wstill be a lot of methods to deal with the problems of agaeing populations.