"Known" is the past participle.
Had known is the past participle.
The past participle is known.
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."
The past participle of drinking is drunk. The past participle of know is known.
Known is already the past participle of know.
The simple past tense is knew. The past participle is known.
The simple past of know is knew and the past participle of know is known.
The past tense of "know" is "knew", and the past participle is "known".