verb. So its correct past and past participle forms are both "dragged."

Apparently, some incorrectly use "drug" as a past tense in some parts of the country and it is "accepted." But the correct grammatical form is "dragged."

The statement reads like this: "I have climbed ..., swum ..., and piloted ...." The initial "have" is applicable to and used with the participles of the verbs following. Both "climb" and "pilot" are regular verbs. "Swim" is an irregular verb, which is why its participle "swum" sounds somewhat jarring.

Sorry, an early incarnation as an English teacher occasionally resurfaces.