which one is correct and why ?
1- I will help you once I understand how it works or 2- I will help you once I understood how it works
which one is correct and why ?
1- I will help you once I understand how it works or 2- I will help you once I understood how it works
Where is the past tense? You are using a future tense sentence, the understanding (and help) will come in the future. You first need a sentence that has past-tense meaning before asking about the proper usage. However, this is correct:
I will help you once I understand how it works