1. 綠 (luk6): This is the most common and general term for green.
2. 青 (cing1): This is a more specific term for certain shades of green, especially a pale or bluish green. It can also mean "young" or "immature" in other contexts.
So, depending on the specific shade of green or the context, you can use either 綠 (luk6) or 青 (cing1).