1: Generally to form the past of regular verbs we will increase ed.
examples: listen - listened start - atarted
2: Verbs ending in "e" is added the "d"
examples: complete - completed lived - lived
3: Verbs that end in "y" precede by a vowel increase will "ed"
examples: enjoy - enjoyed play - played
4: verbs ending in a consonant preceded by a sigle vowel and has the
strongest voice on the last syllable will double the consonant and increase "ed"
examples: stop - stopped scrub - acrubbed