The present perfect tense consists of the auxiliary verb "have/has" plus the past participle form of the main verb. It is used to describe actions or situations that occurred at an unspecified time in the past. The adverbs "ever" and "never" are also used with the present perfect tense. "Ever" is typically used in questions to mean "at any time" and "never" has a negative meaning of "not at any time." Examples are provided to illustrate the proper usage of these adverbs in affirmative and interrogative sentences.