It seems that in many situations where I might use the word "only"only in English, either "nur"nur or "erst"erst is used in German. I have the rather fuzzy idea that "erst"erst is used for "only"only in the sense of "something that only happened once" something that only happened once (e.g. "He only went there to see the museum"He only went there to see the museum) whereas "nur"nur would be used for a general rule (e.g. "She only likes working when it's raining"She only likes working when it’s raining). Even
Even if that'sthat’s roughly right, is there more to it than that? How about something like "I only have two biscuits leftI only have two biscuits left?"