keep a weather eye on something idiom
密切关注（某事）
to watch a particular situation closely to see what happens
They are well accustomed to keeping a weather eye on currency movements. 他们非常习惯于密切关注货币走势。
Your weight can be a strong indicator of your general health, so it's important to keep a weather eye on it. 体重可以作为整体健康状况的一个强有力的指标，所以密切关注很重要。