Regular verbs form their past tense and the past participle by adding "-ed" in the base (simple present) form. There are the following patterns for making regular Verbs:
A: Base form (simple present) doesn't end in "e". We add "-ed" in base form to make the past tense and past participle.
Example: abandon -- abandoned -- abandoned
B: Base form (simple present) ends in "e". We add "-d" in base form to make the past tense and past participle.
Example: abase -- abased -- abased
C: We repeat the last letter of the base form (simple present) in the past tense and past participle before adding "-ed".
Example: rag -- ragged -- ragged
D: Base form (simple present) ends in "y" (and there is a consonant before "y"). We replace "y" with "i" in the past tense and past participle before adding "-ed".
Example: accompany -- accompanied -- accompanied
01A. Regular Verbs -- Pattern - 1
Base form (simple present) doesn't end in "e". We add "-ed" in base form to make the past tense and past participle.