Villagers Li and Chen are relatives and they often exchange experiences in raising livestock and poultry. The villagers, Li and Chen, are related and often share their experiences in raising livestock and poultry. Li has a hobby
long as raises the fish, he must raise the duck; Chen also has a hobby, if does not raise the pig, he certainly does not raise the duck.
If villager Li raises both fish and ducks, he will raise pigs.