The past tense in Russian is very simple. The conjugation group doesn't matter; the specific pronoun in use doesn't matter; the only thing you have to worry about is the gender of the subject!
| masculine | feminine | neuter | plural |
|---|---|---|---|
| stem + ending + л | stem + ending + ла | stem + ending + ло | stem + ending + ли |
| я/ты/он готовилI/you (singular)/he prepared | я/ты/она готовилаI/you (singular)/she prepared | оно готовилоit prepared | мы/вы/они готовилиwe/you (plural)/they prepared |
When using the past tense, it's important to understand perfective/imperfective verbs. A perfective verb indicates a finished action, while an imperfective verb is one that is in progress or continuous. Therefore, the present tense always uses imperfective verbs, while the past tense often uses perfective verbs.
Almost every verb has a perfective and imperfective aspect. Unfortunately, there's no trick for figuring out a verb's perfective form from its imperfective or vice versa. Perfective verbs often look like their imperfective form with a prefix like за, по, у, or с (for example), or some other small change.
Imperfective and perfective verbs can both be used in the past tense to mean slightly different things. For example, if you wanted to say we talked, you would use a perfective verb (сказать), whereas if you wanted to say we were talking, you would use an imperfective verb (говорить).
So, when should the perfective aspect be used, and when should the imperfective?:
| Perfective | |
|---|---|
| a finished action, completed once or a specified number of times | я выпила своя чашка чаяI drank my cup of tea |
| something that was expected to happen, but didn't | я сегодня не выпила своя чашка чая, потому что у меня закончился чайI didn't drink my cup of tea today, because I ran out of tea |
| Imperfective | |
| an action completed many times or habitually | я пила своя чашка чая каждое утроI drank my cup of tea every morning |
| an action completed over a specified time | я пила своя чашка чая один часI drank my cup of tea for/over one hour |
| to represent the past tense of 'be' | я пила своя чашка чаяI was drinking my cup of tea |
| an action not completed | я не пила своя чашка чаяI didn't drink my cup of tea |
Notice the pronoun is я, and the feminine form of the verb is used- this would be someone with feminine pronouns speaking.