variable reference

例句：

1. 1.The weather is a variable factor in predicting the outcome of a sporting event.
   天气是预测体育赛事结果的一个可变因素。
2. 2. The amount of sugar in the drink can be varied to suit different tastes.
   饮料中的糖分含量可以调整以适应不同口味。
3. 3. The team's performance was influenced by the variability of their opponents.
   球队的表现受到对手实力变化的不确定性影响。