A person may contribute vocals to some (solo album).Logical formLearned from8 sentences. A burning of fossil fuels may contribute to global warming.Logical formLearned from8 sentences. (Baby boomers) may contribute.Logical formLearned from8 sentences. A male may contribute thoughts.Logical formLearned from8 sentences. An economy may contribute.Logical formLearned from8 sentences. A dollar may contribute to a surge.Logical formLearned from8 sentences. Some factors may contribute to a turnaround.Logical formLearned from8 sentences. Some sliding scale may be contributed.Logical formLearned from8 sentences. An exploitation of an issue may contribute to alienatting support.Logical formLearned from8 sentences. Coal-fired (power plants) may contribute to global warming.Logical formLearned from8 sentences. Troubles may contribute to a refusal.Logical formLearned from8 sentences. Officials may contribute.Logical formLearned from8 sentences. A person may contribute one.Logical formLearned from8 sentences. Some factor may contribute to a crash.Logical formLearned from8 sentences. A male may contribute to dozens of albums.Logical formLearned from8 sentences.