A collection can be sad.Logical formLearned from49 sentences. A book can be sad.Logical formLearned from48 sentences. Songs can be sad.Logical formLearned from48 sentences. A next day can be sad.Logical formLearned from48 sentences. A performance can be sad.Logical formLearned from48 sentences. A failure can be sad.Logical formLearned from48 sentences. A coincidence can be sad.Logical formLearned from47 sentences. Persons may feel sad.Logical formLearned from47 sentences. Emotions can be sad.Logical formLearned from47 sentences. Posts can be sad.Logical formLearned from47 sentences. A matter can be sad.Logical formLearned from47 sentences. A self can be sad.Logical formLearned from47 sentences. A disappointment can be sad.Logical formLearned from47 sentences. A number can be sad.Logical formLearned from46 sentences. A list can be sad.Logical formLearned from46 sentences.