expression, noun · a statistical or numerical measure used to monitor and track changes in a specific variable or economic sector

消费者物价指数是衡量通货膨胀程度的一个重要指标。

noun · the mathematical power to which a base is raised, or relating to exponential functions and growth patterns

在这道代数题中，我们需要首先确定表达式里的底数和指数。