The past tense of "swell" is "swelled."
The past of "swell" is "swelled" and the past participle is "swollen."
The past participle of "swell" is "swollen".
swelled My toe swelled up last night.
The simple past is had.
The past simple of "have" is "had."
The present participle is swelling. The past participle is swelled.
Past simple and simple past are both the same thing. They are both the past tense of a verb.
The simple past tense is climbed.
The simple past and past participle are both 'had'.
The simple past and past participle are both brought.
The past simple of "study" is "studied."