主权国拖欠债务也绝非天方夜谭。

Sovereign default is far from inconceivable.

国际公法一直被视为是调整主权国关系的一套原则和规则。

Public international law has been regarded as a system of principles and rules designed to govern relations between sovereign states.

上述四个WTO成员相互之间的关系既是WTO体制中平等成员之间的关系，也是同一主权国家中不同关税区之间的关系。

The relations among the four members are not only the relations of equal members within the WTO regime but also the relations of different customs regions within a sovereign State.