Imagined is the past participle of imagine.
Imagined is already in past participle form. It is the past tense and past participle of imagine.
Your answer is unfolded Imagine it like this "many times I have UNFOLDED a shirt".
The past participle of "do" is "done." The past participle of "have" is "had."
The past participle of "am not" is "have not been."
The past participle of "do" is "done."
The past tense of "have" is "had," and the past participle is also "had."
The past participle of the word "have" is "had."
The past participle of "am, are, is" is "been."
The past participle of "will" is "willed."
The past participle is thought.
The past participle of "to" is "been." The past participle of "be" is also "been."
Being is the present participle. The past participle is been.
The past tense and the past participle is "answered".