Students may learn about ancient civilisations.Logical formLearned from2 sentences. A world-city may undergo civilisations.Logical formLearned from2 sentences. A region may undergo civilisations.Logical formLearned from2 sentences. Contact can be with civilisations of the world.Logical formLearned from2 sentences. Societies may range from civilisations.Logical formLearned from2 sentences. Civilisations can be continuous.Logical formLearned from2 sentences. Clashes can be between civilisations.Logical formLearned from2 sentences. A clash can be between civilisations.Logical formLearned from2 sentences. A time may undergo civilisations.Logical formLearned from2 sentences. Civilisations may undergo a demise.Logical formLearned from2 sentences. Civilisations may die.Logical formLearned from2 sentences. Civilisations may destroy themselves.Logical formLearned from2 sentences. Civilisations can be in the past.Logical formLearned from2 sentences. A threat to civilisation may erase lines of rivalry.Logical formLearned from2 sentences. An originator may pertain-to a (civilisation crusade).Logical formLearned from2 sentences.