The past participle (and simple past) is earned.
The past participle is produced.
The past participle is traded.
Yes, the word 'bartering' is the present participle of the verb 'to barter'. The present participle of the verb is a gerund (a verbal noun); for example: Very few people are skilled in the art of bartering.
Barter system
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 participle of the word "have" is "had."
The past tense and the past participle is "answered".
The past tense of "have" is "had," and the past participle is also "had."
The past and past participle for "buy" is "bought."
"Sold" does not have any past participle; it is the past participle of "sell".
The past participle of "was" is "been" and the past participle of "were" is also "been".
Being is the present participle. The past participle is been.
Eating is the present participle; eaten is the past participle.
The past tense is was or were.The past participle is been.
The past participle is thought.