PAST Perfect Tense (Simple sentences)
examples
Subject
Had
Verb-3rdform
Objects
He had worked.
I had worked.
Jack and Sam had worked.
PAST Perfect  Tense (negative sentences)
Subject
had
not
Verb-3rdform
Objects
He had not worked.
I had not worked.
Jack and Sam had not worked.
Present Perfect  Tense (Interrogative sentences)
Had
Subject
Verb-3rdform
Objects
Had  he worked?
Had  I worked?
Had Jack and Sam worked?
Present Tense (Interrogative and negative sentences)
Had
Subject
not
Verb-3rdform
Objects
Had  he not worked?
Had  I not  worked?
Had it not  worked?
Had Jack and Sam not worked?
READ :  Present Perfect Continuous Tense Rule | Perfect Tense Learning