问答题 The dimensions of tourism are astonishing.In 2012, the U.N.tourism organization celebrated reaching 1 billion international trips in a single year.In gross economic power it is in the same company as oil, energy, finance and agriculture.At least one out of every ten people around the world is employed by the industry, according to Wolfgang Weinz of the International Labour Organization.
【正确答案】1 billion.
【答案解析】文章第一段第二句提到“在2012年,联合国旅游组织庆祝国际旅行人次在一年之内达到10亿人次”。因此,应填入1 billion。