customs wall的用法和樣例：
例句
- Within a few months, all customs barriers, quantitative restrictions and discriminatory practices were swept away.
短短几個月，一切關稅壁壘，配額限制，以及各種差別對待的慣例都一掃而光。 - Suppose we make our tariff wall so high that it becomes absolutely prohibitive, and no imports come in from the outside world at all.
假定我們設立的關稅壁壘很高，完全是禁止性的，讓人根本不可能從國外進口商品。
