free of customs

例句：

1. 1. The package is free of customs duties.
   这个包裹免关税。
2. 2. We are duty-free when we travel abroad.
   我们出国旅行时是免税的。
3. 3. The goods are exempt from customs due to their high value.
   由于这些商品价值高，它们免关税。