Irregular verbs do not follow the regular pattern of adding -ed to form the simple past and the past participle. These verbs can be placed into three groups based the number of changes there are from the base form. Some have two changes from the base form. For example, the simple past of "take" is "took," and the past participle is "taken" (two changes from the base form). Others have only one change. For example, both the simple past and the past participle of "say" are "said" (one change from the base form). Some have no change at all. For example, both the simple past and past participle of "put" are "put" (no change from the base form). The irregular verbs can also be studied in subgroups based similarities in pronunciation. For example, one subgroup includes "bind," "find," "grind," and "wind." Their irregular simple past and past participle forms share similar pronunciation (bound, found, ground, and wound). Studying the English irregular verbs by grouping them according to the number of changes from the base form and similarities in pronunciation will make learning these important forms easier.