A system can be constituted-of-or-filled-with exchanges.Logical formLearned from19 sentences. A prisoners may undergo an exchange.Logical formLearned from19 sentences. Shellings may undergo an exchange.Logical formLearned from19 sentences. Exchange can be for a concession.Logical formLearned from19 sentences. Hostages may be freed in exchange.Logical formLearned from19 sentences. An (exchange rate) may undergo movements.Logical formLearned from19 sentences. An (exchange rate) may undergo a devaluation.Logical formLearned from19 sentences. A (stock exchange) can be vibrant.Logical formLearned from19 sentences. (Exchange rates) may undergo determination.Logical formLearned from19 sentences. Exchange can be for freedom of hostages.Logical formLearned from18 sentences. Some countries may carry_out exchanges.Logical formLearned from18 sentences. Exchanges can be with counterparts.Logical formLearned from18 sentences. An (exchange rate) may move.Logical formLearned from18 sentences. Exchanges may start.Logical formLearned from18 sentences. Exchanges can be between political parties.Logical formLearned from18 sentences.