To add to my previous response:

1. New speakers often say wrongly:
I heard John talkS to her.
2. I heard John talk (infintive) to her.
3. I heard John talking (cont participle) to her.
4. Whilst the infinitive in (2) and the cont participle in (3) do not have a tense by themselves, they actually "borrow" the tense from the antecedent verb "heard". Since "heard" is in the past tense, it is understood that "talk" is in the simple past tense in (2); and "talking" is in the past cont tense in (3).