With a preposition:That was the only time to leave my country an

With a preposition:
That was the only time to leave my country and set foot ______foreign soil.
【正确答案】：on
【题目解析】：当名词短语前由序数词(the first, the second, etc.)、一般序数词(the last, the next)、最高级的形容词(the best, the most...，etc)或the only修饰时，不定式可用作名词短语的后置修饰语。Set foot on踏上……。