风向标用英语怎么说？

风向标

例句

• The outcome of tomorrow's elections will be studied carefully as a signpost of voter intentions on the really big day this year... 明天的选举结果会被作为今年大选的选民意愿风向标来仔细研究。
• Early American weathervanes were most often cut from flat wooden boards... 美国早期的风向标大多截自平直的木板。
• IBM is considered the bellwether stock on Wall Street. 国际商用机器公司的股票行情被视为华尔街股市的风向标。