mindmap root((发现)) discover may apply to something requiring exploration or investigation or to a chance encounter and always implies the prior existence of what becomes known: ~ed the source of the river. ascertain implies an awareness of ignorance or uncertainty and a conscious effort to find the facts or the truth: will try to ~ the population of the region. determine largely scientific or legal in usage, emphasizes the intent to establish the facts or to decide a dispute or controversy: unable to ~ the exact cause of the disease. unearth implies a bringing to light of something forgotten or hidden: ~ old records . learn implies acquiring knowledge either with little effort or conscious intention: ~ed the truth by chance; OR by study and practice: spent years ~ing Greek.