A birthday can be a 9th.Logical formLearned from21 sentences. A book can be for a birthday.Logical formLearned from21 sentences. A person may do on a birthday.Logical formLearned from21 sentences. An one can be for a birthday.Logical formLearned from21 sentences. A birthday can be a 6th.Logical formLearned from21 sentences. Birthday can be fun.Logical formLearned from21 sentences. A person may miss birthdays.Logical formLearned from21 sentences. Birthday may thank a person.Logical formLearned from21 sentences. (Birthday parties) may pertain-to persons.Logical formLearned from21 sentences. A month can be until a birthday.Logical formLearned from21 sentences. Birthday can be to a world-city.Logical formLearned from21 sentences. A (birthday present) may pertain-to a dad.Logical formLearned from21 sentences. A person can be a (birthday girl).Logical formLearned from21 sentences. Dinner can be on a birthday.Logical formLearned from21 sentences. Persons may talk about a birthday.Logical formLearned from21 sentences.