Kneed is the past participle of knee.
Knee is a regular verb so both past and past participle are knee + ed kneed
present, hurt: They always hurt me. past, hurt: I hurt my knee yesterday. past participle, hurt: She has hurt her knee badly.
The past participle of "am not" is "have not been."
The past participle of "do" is "done." The past participle of "have" is "had."
The past tense of "have" is "had," and the past participle is also "had."
The past and past participle for "buy" is "bought."
Being is the present participle. The past participle is been.
Eating is the present participle; eaten is the past participle.
The past participle is thought.
"Did" is the past and "done" is the past participle.
The past participle is had.
The past participle of "do" is "done."