Swims is already plural.
The singular is swim.
Swam, as in all of the boys swam last week.
swum
swam
No. The verb has an irregular past tense.The present tense is swim, or swims.The past tense is swam. The past participle is (have) swum.
The past tense of swim is swam.
The past tense is swam.The future tense is will swim.
Yes, "could" is the past tense of "can." For example, "I can swim" changes to "I could swim" in the past tense.
have in past tense is had
The past tense of "have" is "had."
The past tense of have is had.
The past tense of 'spell' is 'spelled'. 'Spelt' is also used in British English.
The simple past tense of swim is "swam". The past participle of swim is "swum".
The past tense of "settle" is spelled as "settled".
The past participle of "swim" is "swum". The simple past tense is is "swam".
The past tense is benefited.