Stacked is the past tense of stack.
No the word stacked is not a noun. It can be an adjective meaning arranged in a stack. It can also be a verb where it is the past tense of the verb to stack.
the past tense of am is was and the past tense of has is had
The past tense of "has" is "had" and the past tense of "have" is "had."
Was and were are both the past tense of be. The present tense is: I am he is you are they are The past tense is: I was he was you were they were
"will be" is the future tense of "be". The past tense of "be" is "was/were".
The past tense is she did.
The word "were" is past tense. It is the past tense of the verb "to be."
The past tense of "will" is "would". The past tense of "to be" is "was" or "were".
HAD is the Past Tense of TO HAVE.
The past tense of "you will not" is "you would not."
The past tense of "am" is "was" and the past perfect tense of "has" is "had."
The past tense is had.