Billionth
num. 第十亿个, 十亿分之一
🗣️ 情景例句
Nice work.
干得好。
Mary gave birth to a baby last week.
玛丽上星期做妈妈了。
Professor Ronald Bracewell, a leading American radio astronomer,argued in Nature that such a superior civilization, on a visit to our own solar system,
假如有如此高级文明生命访问了我们的太阳系，