A (flu vaccine) may pertain-to a year.Logical formLearned from41 sentences. Signs can be constituted-of-or-filled-with flu.Logical formLearned from41 sentences. A game can be with a flu.Logical formLearned from41 sentences. A spread may pertain-to (bird flu).Logical formLearned from41 sentences. A spread can be constituted-of-or-filled-with (bird flu).Logical formLearned from41 sentences. Presence may pertain-to a (bird flu virus).Logical formLearned from41 sentences. A (bird flu case) may pertain-to a country.Logical formLearned from40 sentences. A virus may cause (bird flu).Logical formLearned from40 sentences. A (bird flu strain) can be virulent.Logical formLearned from40 sentences. A (bird flu outbreak) may kill some persons.Logical formLearned from40 sentences. A (flu pandemic) may kill millions.Logical formLearned from40 sentences. A (bird flu) can be virulent.Logical formLearned from40 sentences. A fatality can be from (bird flu).Logical formLearned from40 sentences. Some persons may die of a flu.Logical formLearned from39 sentences. A boy may die from (bird flu).Logical formLearned from39 sentences.