The present participle is "costing", and the present indicative tense is "cost" except for the third person singular, which is "costs".
present-cost present participle-costing past-cost past participle-cost
Lead is present tense. The present participle is leading. Led is the past tense and past participle.
The past tense is ate.The present tense is:I/You/We/They eat.He/She/It eats.The past participle is eaten.
The past participle is done. The simple past tense is did. The present participle is doing.
The past tense and past participle is equipped; equipping is the present participle.
Forget is the present tense. The past tense is forgot, the past participle is forgotten, and the present participle is forgetting.
Known is the past participle of know know / knows = present tense knew = past tense known = past participle knowing = present participle
Strike is the present tense, and struck is the past tense and past participle.
Seek is present tense, and seeking is the present participle. Sought is the past tense and past participle.
The past tense is brought. The past participle is brought. The present participle is bringing.
Pulled is the past tense and past participle of pull. Pulling is the present participle.
The past tense is bit. The present participle is biting. The past participle is bitten.