premise: A black dog is swimming with a ball in his mouth. hypothesis: A black dog found a ball in the water and is bring it back to its owner.
entailment: A black dog found a ball in the water and is bring it back to its owner as the black dog was swimming with a ball in his mouth which must be because the dog found a ball in the water to be retrieved by the dog's owner.|entailment: Swimming implies in the water, and ball in his mouth implies bring it back to its owner.|entailment: Swimming can only be done in the water.