The Past Tense Endings
The Past Tense of a verb indicates that the action indicated by the verb occurred in the past. The Past Tense ending for both conjugations is -л + gender marker, -o for neuter, -a for feminine, nothing for masculine, in the singular and -и in the plural. The past tense of сказа- "say, tell" is сказа-л-, as shown below:
(он) сказал "he/it said"
(она) сказала "she/it said"
(оно) сказало "it said"
(они) сказали "they said"
The stem does not change if the past tense ending is added to a vowel stem; however, this ending doesn't like consonants and usually makes some adjustments to consonant stems. We will talk about it when we learn the Rules of Combinations.