annual mean的用法和樣例：
例句
- The latter factor drops out when average annual temperatures are considered.
若考慮年平均溫度，則可將后一個因素除掉。 - Although the prevalence increased with age, the annual change in mean refractive status was slower in the schoolchildren of mountain aborigines.
儘管年齡愈高，近視盛行率愈高，但原住民學童之年平均屈光變化似乎較緩慢。
