题目

When Carla Fisher and her husband announced plans to travel the globe with their young daughters for a year, some friends called them crazy.     Seven years later, with wonderful memories and a book documenting their world travel, the Fishers now seem like global trailblazers (先驱者).     “It’s really encouraging to hear that many other people want to educate their kids in that manner,” said Fisher. Some parents are trying to raise knowledgeable and open-minded “world citizens”. Others want to give their children the skills they’ll need to compete globally. “There is a（2013?泰安三模）下列说法正确的是（　　）A．酸雨样品露天放置一段时间，酸性增强，是由于雨水所含成分被氧化的原因B．CH4、NH3、PH3的热稳定性逐渐增强C．因为酸性：HC1＞HF，所以非金属性：Cl＞FD．钠原子在反应中失去的电子比铝原子少，故钠的金属性比铝弱