### Chinese: 看过等级分类的你应该已经发现，橄榄油的酸度是一个非常重要的指标。
### English: After reading the classification by levels, you may find that acidity is a very important index.
### Errors: There is a major error at "by levels".

### Improved English: After reading the classification, you may find the acidity of olive oil is an important index.