1) A grocery store is a store that primarily sells food, but it may also carry other household items. A supermarket is a type of grocery store that is typically larger in scale and carries a wider selection of items.
2) Kaufland, Auchan, Carrefour, Lidl, Cora
3) My favourite supermarket chains is Lidl. I can get almost everything you need in one supermarket shopping trip, and it is often cheaper than the smaller shops. You also only need to find one parking spot, rather than going shop to shop.
4) When I go to the supermarket I always buy milk and cereals to have breakfast in the morning. Then I buy the bread with the salami and ham to make a sandwich. I buy potatoes and then fry them. I also buy drinks like water or Coca Cola and finally some sweets like chocolate bars or candies.
