The first shiploads of immigrants bound for the territory which is now the United Sates //crossed the Atlantic more than a hundred years after the 15th-and-16th-century explorations of North America.

【词】bound for: 开往某地; Atlantic: n. 大西洋; territory: n. 领地; exploration: n. 探索

【析】面对长难句，我们首先需要划分句子结构，句子结构优先考虑从属连词(what,when,which等)，该句中从属连词为which, 所以从句为which is now the United States，从句为定语从句，用来修饰前面的territory, 进而确定在crossed一词前面给断开来，crossed为主句的谓语动词，从而句子主干成分为The first shiploads of immigrants crossed the Atlantic。主谓之间诸如 bound for the territory which is now the United States为后置定语修饰主语，在翻译过程中需要前置到主语前面修饰，句末more than a hundred years after the 15th-and-16th-century explorations of North America为时间状语，翻译过程中需要前置。

【译】在15,16世纪北美探索过后的100多年内，第一艘开往当今美国这片土地的移民船，穿过了大西洋。