Скажите пару слов на эту тему, можно даже не по-. "if every person swept their own doorstep, the city would soon be clean"

This expression means that everyone should be doing their part and taking personal responsibility for  his or her  own actions, rather than expecting someone else to get it done for them. it's easy to criticize and complain, it's harder to get things done. also it means that to accomplish a big project (clean city) one has to start small (sweep their doorstep) and work with others as a team.

There is one persone i'd like to tell you some words about. this is my elder  sister vitalina. she's 25. i admire her and would like to resemble her.     she's a very optimistic person: whatever   the situation is. vitalina has a long blond hair and she toll and so beautyful.she always keeps smiling. vitalina is also very helpful.   she is very persistent, enthusiastic and hardworking. at the same time, my sister is a wonderful wife and mother of two kids. i wish i could be the same person as my sister is. 

There is an uncomfortable chair in that office, i'll never go there else. he told us only an incomplete story of what have happend there. the explorers finally reached an unknown land. an independent country announced a referendum to decide whether people want to stay free or to join another country. they are planning to organise an informal party, but i don't think they'll  do it an unbuilt cottage can stay on its place for ages. immigrants decided to settle on an unpopulated territory. nobody wants to stay in an inhospitable place like that/