这个国家的实际名称和英文名称似乎有很大差异，那么， Japan的英文单词Japan是怎么来的呢？

是的， once是一个连词，意味着when （ when 〜）， as soon as （ as soon as 〜）。 once you've dealt with that one句子as soon as you've dealt with that one. once you've dealt with that one句子as soon as you've dealt with that one.我能理解示例： Once the item is back in stock, I'll let you know. （有货时，我会通知您。）示例： Once the test begins, you should be quiet. （测试开始时，您必须保持安静。）