The English verb system in its basic structure is very regular and fairly free of inflection. It does not consist of 12 to 17 tenses as some sources claim. It is a combinatorial system whose building blocks are: two simple forms (traditionally called ‘simple present’ and ‘simple past’), two auxiliaries (BE and HAVE) and two participles (verb + ing, commonly called ‘present participle, and ‘past participle’). Together they can be combined to form various structures of different semantic complexity. This I demonstrate with the Verb Structure Circle.