Known is already the past participle of know.
"Known" is the past participle.
The past participle is known.
Had known is the past participle.
There is no past participle of knowing.Knowing is the present participle of know. The past participle of know is known
The past participle is known.
The past participle is known.
The past participle is known.
The past participle of "know" is "known."
Known is the past participle of know know / knows = present tense knew = past tense known = past participle knowing = present participle
The past participle of drinking is drunk. The past participle of know is known.
There is no such thing as a future participle.The past participle is known and the present participle is knowing.
The simple past tense is knew. The past participle is known.