Firstly, I think you misunderstood the prompt. You were asked to discuss the advantages and disadvantages for people who move to cities
. Instead, you discussed about said aspects for the general development.
Secondly, I have spotted several mistakes in word choice
Should have been "life
"...to have a job or to
a better future for not only ...
Run-on sentence, could have been divided by a comma, and perhaps be reworded as "...a better future, not only for them, but also for their kids
on the development at all
The phrase "at all
" at the end may confuse reader to think that you meant young people leaving their hometowns doesn't have any negative.
affection on economic
" was wrongly used as it means "a feeling of liking for a person or place" according to the Cambridge dictionary. Whereas I suppose you meant "adverse effect
While there are only old
Personally, I think using "when
" would be more fitting than "while
activities will be lower
If you are using "lower
" as an adjective, I think it would be more appropriate to specify being lower than what exactly. Or, you could have used the passive form of the verb as "lowered
So, they all feel lonely because ...
The following argument of the first sentence made no sense. The loneliness from lacking attention has nothing to do with having no one in the family who is capable of working.
Those are all I can spot and correct, so far. Hope you find this helpful