Dogs can eat snow peas, string beans, carrots and apples. Nuts, chocolate, scallions, onions, and grapes are generally no good for dogs. Small quantities are obviously not a big deal, but repeated amounts or large amounts are toxic to dogs.
Certain dogs with health issues should also watch what they eat so always consult with a vet to make sure if a certain diet is ok.
I hope this answers you questions. Please let me know if you have any other problems or questions, I'll be happy to help.