欧盟拒绝了英国提出的在退欧后暂时留在关税联盟中的方案，因为这意味着英国既享受到自由贸易的好处，又可以不允许欧盟公民的自由流动。
The EU rejected British offers to remaintemporarily in the customs union after Brexit, because that would allow the UK to enjoy the benefits of tariff-free trade without having to permit the free movement of EU citizens.