帮我改正一下这盘初中小作文的语法错误

Now and then.
People's life changes better.In the past,people also poor.because the fiance is not development.the family is big.commonly, every family has only one child now.and the traffic is faster.the education is better.Almost everyone can go to school..people are getting healthier.because madicine is advanced.there are less illness.so people can live longer than they did.but there are many junk food now.but I think pollution of the enviroment is very serious.the air doesn't clean.and we only can play at home.we only can play computer, watching tv.in the past,we can play in the big and spacious playground.
In my opinion, i think that the present has politically progressed than the past. the living has improved.

Now and then
People's life is changeing better.In the past,people were poor,because the finance didn't develop much.The family was big.Commonly, there is only one child in each family now.And the traffic is better.The education is be