The complex rules of origin that feature in preferential deals are also worrying.

那些以特惠协议为特征的复杂的“原产地规则”也令人担忧。

Pesky rules of origin, which prevent many Mexican manufacturers from selling goods in America, do not apply to Colombian cocaine processed in Mexico.

这个公约禁止对毒品生产进行监管和征税。此外，原产地规则阻止很多墨西哥制造商在美国销售产品，却不适用于在墨西哥加工的哥伦比亚可卡因产品。

As well as restricting trade, rather than liberalising it, they will make it tricky to agree more permissive rules of origin for cars in future trade deals.

和限制贸易一样，他们不会将其自由化，而是让它变得棘手从而无法在以后的汽车贸易协议中实施更加宽松的原产地规则。