Which 'single' (nie, ja dalabym slowo 'only') child does not dream about having a brother or sister to play with? Certainly having 'a' (po co to 'a' przed l. mn-siblings?) siblings has many benefits (przecinek przed slowem 'but' bo tutaj dajesz druga mysl) but there are two sides to every 'question' (to nie jest question, ale moze 'story' czy cos takiego) ,thus, I WILL try to display both advantages and disadvantages of being a member of a 'numerous' (cos mi sie to slowo nie za bardzo podoba - poszukaj inne) family.
To begin with, the greatest benefit of being brought up with many brothers or sisters is (brak przedimka) ability to solve problems and get 'in' (zle slowo, tu ma byc ON) with other people. Indeed, arguments about toys or clothes are unavoidable, 'therefore' (daj inne slowo, np. consequently - sprawdz w slowniku co to znaczy), people who have such 'expirences' (blad ortog) are 'made' (za silne slowo, tu trzeba napisac 'przyzwyczajemi') to deal with 'it' (zle 'experiences' to jest l. mn, tu tez trzeba l. mn) and meet (kogo? czego? musisz napisac) halfway.
Secondly, children 'form' (ortog) a numerous family always have somebody to play with.
'Surely' (za silne i dziwne slowo tutaj, nie mozesz tak twierdzic i pisac, ze to jest napewno, bo nie wiesz - daj cos innego), siblings who go to school together know that the more the 'marrier' (blad ortog).
On the other hand, living in a big family may be overwhelming (ale dla kogo? musisz napisac).
Additionally, it happens that younger children are 'estimated' (calkowicie nie rozumiem uzycia tego slowa tutaj, daj cos innego) in terms of their older brothers and sisters, 'therefore' (za silne slowo, wystarczy 'so'), they often feel 'underestimated' (tego nie rozumiem, zle slowo) and distressed.
In conclusion, growing up in a numerous family has not only virtues but also drawbacks.However, It is essential to take into account the fact that bonds between siblings are inextricable,thus,if you happen to have a brother and sister, they are certainly worthy of becoming your best friends. (To zdanie jest za dlugie, duzo sie w nim dzieje, podziel to)
Nevertheless, whether you come from a big family or a small one everything depends on 'proper' (no to jest temat rzeka - musisz napisac dokladnie co rozumiesz przez to slowo) upbringing.