a prime source of information的用法和样例：
- Because happiness is now considered more an entitlement than a pursuit among citizens of prosperous countries, unhappiness has become a sign of failure, of weakness, and a prime source of dread.
- He's totally unreliable as a source of information.
- The historian search for primary source of information about the past.
- An infallible guide; an infallible source of information.