A purpose clause is the part of the sentence which explains why the action in the main verb took place. They are most commonly used in Latin with the word 'ut' or the word 'ne' followed by a subjunctive verb, because the action is potential. They can be translated by introducing the purpose clause with 'in order to' or 'in order not to' depending on whether you have 'ut' or 'ne'. For example, take the Latin sentence ‘puer currit ut canem capiat’. Everything after ut is part of the purpose clause. Begin by translating the main verb of the sentence which is in the active mood 'currit' and its nominative subject 'puer' to make 'The boy is running'. Next translate the subjunctive verb 'capiat', ('catch’) and any other parts of the sentence, here the accusative object 'canem', ('dog'). The 'ut' can be translated as 'in order to' and so the translation of the sentence is 'The boy is running in order to catch the dog'.