Position precedencerule. When resolving the float box position, the optimum vertical constraint takes precedence over the optimum horizontal constraint.
位置优先原则：在判断浮动框位置时，最佳垂直限制优于最佳水平限制。
2
The reason is that the tests due date rule for Test3 has precedence over the tests due date rules for Test4 and Test5.
原因在于Test3的到期日期规则优先于Test4和Test5的测试到期日期规则。
3
If there is more than one rule, the processor resorts to an algorithm from the XSLT specification for deciding which rule takes precedence.