(Energy sources) may contribute to global warming.Logical formLearned from10 sentences. Al-ansary may contribute reporting.Logical formLearned from10 sentences. A male may contribute some yards.Logical formLearned from10 sentences. Taxpayers may contribute.Logical formLearned from10 sentences. An ability may contribute to relationships.Logical formLearned from10 sentences. Individuals may contribute to a campaign.Logical formLearned from10 sentences. Factors may contribute to growth.Logical formLearned from10 sentences. A writer may contribute to magazines.Logical formLearned from10 sentences. Gains may contribute to a rise.Logical formLearned from10 sentences. Immigrants may contribute to a country.Logical formLearned from10 sentences. (Family members) may contribute to lives.Logical formLearned from10 sentences. Weather may contribute to a crash.Logical formLearned from10 sentences. A weakness may contribute.Logical formLearned from10 sentences. A denudation of hillsides may contribute to (soil erosion).Logical formLearned from10 sentences. Macroeconomic policies may contribute to stability of an international monetary system.Logical formLearned from10 sentences.