• to become aware of, to become aware of sg, to come to know, to discover, to experience, to feel, felt, to find, found, to go through, to learn, to learn, learnt, to meet with, to notice, to observe, to pass through, to perceive
• seasoned, sophisticated, versed, veteran
• experience, observations
• callow, freshwater, green, inexperienced, ingenuous, raw, unfledged, unseasoned, verdant
• he has been around a lot, he has experienced a lot
• callowness, newness, rawness, verdancy
• composition formula, empirical formula, minimum formula
• to come to know, to discover, to find, found