求翻译：美国历史上贸易保护思潮占据主要地位。从美国贸易实践看，在大多数时期，美国是一个高关税国家，但在建国后前期，在欧洲自由贸易运动国际扩散过程中，受自由贸易理论的影响，出现了自由贸易的趋势。在1833年妥协关税法案——它在1942年以前的年代里提供了一种缓慢而稳定的关税减让——通过之后，贸易保护主义的势头有所遏制，尽管1842年以后关税一度有所提高，但在1846年关税法案中又恢复了贸易自由化，并且在1857年加强了这种趋势。是什么意思？

Trends in American history, the dominance of trade protection. From the U.S. trade practice, in most of the period, the United States is a high-tariff countries, but after the founding of the early stage of the international trade movement in Europe, the diffusion process, by the impact of free trad

History of the United States dominates trade protection currents. From the United States trade practice, in most times, the United States is a high tariff countries after the founding, but in the early part of the European Free Trade Association international proliferation Movement in the process, t

United States trade protection thought to occupy a major position in the history. From the United States trade practices of, at most times, United States is a high tariff country, but after the founding of the prophase, international free trade movement in Europe in the diffusion process, influenced