### 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 bags one year, while the shelf life of listening packs is two years or more?
### Errors: There is a major error of incorrect translation includes information not present in the correct translation at "everyone". There is a major error of incorrect translation has stylistic problems at "listening packs". There is a major error of incorrect translation is missing content from the correct translation at "bags".

### 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?