### Chinese: 那么大家肯定会问：为什么袋装保质期是一年，而听装的保质期是两年或更长呢？
### English: Then everyone will definitely ask: Why is the shelf life of a bag one year, while a hearing bag has a shelf life of two years or more?
### Errors: There is a major error at "everyone". There is a major error at "of a bag". There is a major error at "a hearing bag".

### Improved English: Then you may ask: why is the shelf life of milk powder one year in bags and two years or longer in cans?