### 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: But it is not regular enough to accurately predict, about a week or so of tolerance, need to prepare in advance, sometimes bad luck will also turn over (suddenly several days in advance).
### Errors: There is a major error of incorrect translation has stylistic problems at "about a week or so of tolerance". There is a major error of incorrect translation includes information not present in the correct translation at "sometimes bad luck will also turn over". There is a major error of incorrect translation is missing content from the correct translation at "you need to prepare in advance". There is a minor error of wrong grammatical register (eg, inappropriately informal pronouns). internal inconsistency (not related to terminology) at "turn over".

### 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.