An infinitive is the basic form of a verb, meaning 'to...' (for example 'to eat' or 'to dance'). In English, infinitives are two words long, whereas in French they are just one word, ending in 'er', 're' or 'ir'. For example, 'manger' means 'to eat', 'prendre' means 'to take', and 'finir' means 'to finish'. If we want to use an infinitive in relation to a person and a tense, we need to 'conjugate' it, which means slightly changing the word to make it suit the person and the tense. This is something we do in English too! Remember - we can say 'I eat', but we can't say 'he eat' as it doesn't make sense, we need to add an 's' to make it 'he eats'.