My english isn't flawless (You should hear me talking english!!). I have problems with ",", because in finnish we put those everywhere.
"I went to a grocery store(,) because I wanted to buy vegetables(,) for making sallad(,) of course. However(,) I forgot my purse to home(,) and had to come back. When I finally was in the grocery store(,) I noticed that it was closed already."