题目解析:
promptly 表示迅速的,对应 A 选项 quickly 快速的。对应原文:Eventually many of the immigrants moved to unsegregated areas in outer zones; the areas they left behind were promptly occupied by new waves of immigrants.
Promptly 在原句中是用来修饰 occupied 的副词,通过上下文的语境去理解,主要是描述早来的和晚来的种族之间会有矛盾,来的早的最终会移居到 outer zones,留下的地方会被新来的 promptly 地占领。这么看来,还是 A 选项最合适,更符合语境。