题目

A crew of six teenage girls completed a nine-day sailing trip in the US recently，after braving seasickness and strong winds.For the past three years，the Sea Cadet teenagers who set sail were all male.Roger Noakes，who captained the boat，said this was the first time he’d taken out an all-female crew.The girls asked for an a11-girls trip in August this year.The crew set sail along with three adults，Noakes and two Sea Cadet representatives.The original plan was for the girls to sail 24 hours a day in rotating shifts(轮流换班)along the coast and then return.Things turned out differe（2011四川宜宾，9题）染发常用到的着色剂——对苯二胺，化学式为C6H8N2，是一种有毒的化学药品，有致癌性，下列说法正确的是（  ）A．对苯二胺中含N2分子B．对苯二胺中碳、氢、氮元素的质量比为6：8：2C．对苯二胺由6个碳原子、8个氢原子和2个氮原子组成D．对苯二胺中碳元素的质量分数的表达式为