The document summarizes the two main classes of verbs in English: lexical verbs and auxiliary verbs. It provides examples of regular and irregular lexical verbs. There are three primary auxiliary verbs - do, be, have - and ten modal auxiliary verbs - can, could, must, may, might, shall, should, will, would. The document gives examples of how modal auxiliary verbs are used and their special characteristics, such as not taking -s in the third person singular.