PAC versions should be maintained by the certificate-issuing authority; the version should change when the user's group membership information changes.
PAC 版本应该由颁发证书的权威机构进行维护；当用户组的成员关系发生变化时，版本也应该变化。
2
The high scorer from each group was awarded a $15 gift certificate for use in the online store.
每组中最高分奖励 15 美元的在线商店购物卷。
3
Motivation might have been an issue, as the experiment did not count for class credit, though the highest scorer in each group earned a $15 iTunes gift certificate.