PAST PERFECT

 What is it?

Is a verb tense in english used to talk about on action that occurred before another action in the past. It is formed using the verb 'to have' in the past tense (had) followed by the past participe of the main verb. 

AFIRMATIVE:

S + Had + Verb in the past + C

NEGATIVE:

S + Had + Not + Verb in the past `C

INTERROGATIVE CLOSED:

Had + S + Verb in the past + C + ?

INTERROGATIVE OPEN:

Pronouns interrogative + Had + S + Verb in the past + C + ?

EXAMPLE: 

+ She had finished her homework.                                                                                                                -She had not finished her homework                                                                                                            ? Had she finished her homework?                                                                                                              ? What had she finished?