a topic of conversation的用法和样例：
- The weather is a stock topic of conversation.
- The weather is often a topic of conversation, regardless of where people live or what time of year it is.
- Needless to say, the approaching match has been a topic of conversation at the Chelsea training ground.
- Find more opportunities for accidental learning and make it a topic of conversation.
- Since last year, Chinese liquidity, mostly coming through unofficial channels that evade foreign-exchange controls, has become a topic of conversation again in Hong Kong.