Answer:
1.The present perfect is a grammatical combination of the present tense and perfect aspect that is used to express a past event that has present consequences.
2.The pluperfect, usually called past perfect in English, is a type of verb form, generally treated as a grammatical tense in certain languages, relating to an action that occurred antecedent to a contextually aforementioned time in the past.
3.The future perfect is a verb form or construction used to describe an event that is expected or planned to happen before a time of reference in the future, such as will have finished in the English sentence "I will have finished by tomorrow."
For example, “I have just finished writing my essay.” Present perfect can also be used to describe something that happened in the past but is still occurring. For example, “Daniel has worked for Exxon for the past 12 years.” Past perfect refers to how two things that have already happened relate.
