Which one is correct
1. Could you help me with this?
2. Can you help me with this?
I'm confused. Sometimes i hear #1 from people. Isn't could past tense of can? So why use the past tense when asking for help?
It is indeed true that could is the past tense of can. But it is also used in making polite requests. (Example: "Could you help me with this?") The word can is used in situations that are less formal (or more informal).