 Ergatives are in transitive constructions with non-agentive subjects that have an underlying transitive counterpart. Here are two examples that help us to understand the difference between ergative and non-ergative verbs in present-day English. The boy sank the boat versus the boy destroyed the boat. In both cases we have an agentive subject, a transitive verb and an object as a patient. Such sentences can of course be passivised where the byphrase is optional and the subject is now the patient. But what happens if we use these passive constructions as actives? Well, it works for sink as in the boat was sinking or the boat sank, but not for destroy. The boat was destroying is ungrammatical. For this reason, sink is a so-called ergative verb but destroy is not. Here are further examples. The ice was melting and the toilets are flushing involve ergative verbs that have transitive counterparts. The sun was melting the ice and someone is flushing the toilet. In languages other than English, ergatives are often realised as passives or they involve different verbs, like for example in present-day English fall versus fell. By the way, the term ergative is also used to draw a distinction between the case-marking of the subjects of intransitive and transitive verbs in particular languages. The Caucasian languages, for example Georgian, typically use ergative case systems.