Birds may sing.Logical formLearned from760 sentences. Cases can be constituted-of-or-filled-with (bird flu).Logical formLearned from749 sentences. A (bird flu) can be deadly.Logical formLearned from721 sentences. Birds can be tropical.Logical formLearned from720 sentences. A nest may pertain-to a bird.Logical formLearned from705 sentences. A strain can be constituted-of-or-filled-with (bird flu).Logical formLearned from701 sentences. Birds can be endangered.Logical formLearned from687 sentences. Birds may pertain-to air.Logical formLearned from658 sentences. A family can be constituted-of-or-filled-with passerine birds.Logical formLearned from651 sentences. Some cases can be constituted-of-or-filled-with (bird flu).Logical formLearned from642 sentences. Birds may pertain-to persons.Logical formLearned from624 sentences. Birds may fly.Logical formLearned from599 sentences. (Bird flu) can be in a country.Logical formLearned from596 sentences. Outbreaks can be constituted-of-or-filled-with (bird flu).Logical formLearned from592 sentences. Birds can be nocturnal.Logical formLearned from549 sentences.