Three verb forms in English are perfect, progressive and perfect progressive. Each form uses three different tenses: present, past and future.
The perfect form is created by using either of the helping verbs "have" or "had," in conjunction with the past participle of the main verb. For example, the verb "eat" is in its present perfect form in the sentence, "I have eaten my lunch."
The progressive form uses a form of the auxiliary verb "to be" in combination with present participle, which is the "-ing" form of the main verb. For instance, the verb "eat" is in its past progressive form in the sentence, "I was eating my lunch."
The perfect progressive form is created by combining the rules in forming the perfect and progressive forms. For example, the verb "eat" is in its future perfect progressive form in the sentence, "I will have been eating lunch."