XV. Perfect Tense

          The three perfect tenses in English are the three verb tenses which show action already completed. (The word perfect literally means "made complete" or "completely done.")

They are formed by the appropriate tense of the verb to have plus the past participle of the verb.

Present Perfect: I have seen it.
(Present tense of to have plus participle. Action is completed with respect to the present.)

        (+)I/you/we/they + have+ verb 3 + O

        He/she/it + has + verb 3 + O

   (-) I/you/we/they + have + not + verb 3 + O

        He/she/it/ + has + not + verb 3 + O

   (?) Have/has + S + verb 3 + O?

Past Perfect: I had seen it.
(Past tense of to have plus participle. Action is completed with respect to the past.)

         (+) Subject + had + verb III + (complement)

    (-) Subject + had not + verb III + (complement)

    (?) Had + subject + verb III + (complement)

Future Perfect: I will have seen it.
(Future tense of to have plus participle. Action is completed with respect to the future.)

        (+) Subject + will + have + verb III + complement

   (-) Subject + will not + have + verb III + complement

   (?) Will + subject + have + verb III + complement +?

       Some authorities consider the passive voice of certain verbs that are always intransitive to be the perfect tense also.
   Example: They are gone.    Example: He is risen.