### Chinese: 但也不是规律到能精准预测，大概一周左右的公差，需要提前准备，有时候运气差也会翻车（突然提前好几天）。
### English: However, it is not so regular that it can be accurately predicted. The travel time is about a week, so it needs to be prepared in advance. Sometimes, it won't follow the schedule due to bad luck (suddenly several days ahead).
### Errors: There is a major error at "travel time". There is a major error at "it". There is a major error at "prepared". There is a major error at "won". There is a major error at "t follow". There is a major error at "bad luck (suddenly several days ahead".

### Improved English: But it is not so regular that you can precisely predict it; there is a difference of around a week; you need to prepare early and sometimes you may get unlucky and it arrives several days earlier.