回複：later of 4 months from (from MPEP)

It is from MPEP chapter 200 regarding claim of priority. It means this, if your utility application is filed after 11/29/2000 and you want to claim priority from an earlier-filed provisional, you need to let the PTO know within 4 months from your actual filing of the utility patent, OR, 16 months from the filing date of the provisional, which ever is later. Thinking you only have one year from the filing of the provisional to claim priority, the PTO is willing to give you a maximum one year plus 4 months to claim priority, regardless when you file the utility. If you are outside the time limits, it does not mean you cannot claim the priority but since PTO will publish the application somewhere around 18 months from the initial filing, they really like to get your claim in two months ahead of the publication. Otherwise, your claim of priority will not show on the application and you have to do a certificate of correction for the priority claim and pay extra money.