This means that if a user submits a form with a key that has already been used, the form submission will be considered invalid.

这意味着，如果一个用户提交一个含有已用过的密钥的表单，则该表单提交操作将被视为无效。

youdao

This means that if a user submits a form with a key that has already been used, the form submission will be considered invalid.

这意味着，如果一个用户提交一个含有已用过的密钥的表单，则该表单提交操作将被视为无效。

youdao