Verbal group is one of the most complex areas of English grammar. It involves several systems including finiteness, modality, tense, polarity, and voice. Finiteness distinguishes between finite verbs like "eats" in independent clauses and non-finite verbs like "eating" in dependent clauses. The tense system has three terms - present, past, and future - realized through verb forms like "-s", "-ed", and "will/shall". Polarity distinguishes positive verbs from negative verbs marked by "not". Voice distinguishes between active verbs and passive verbs formed with "be" plus the past participle.