题目

下面关于“2”的含义的解释中，正确的是    A．Zn2+中的“2+”表示锌粒带有2个单位的正电荷    B．2NO中的“2”表示2个一氧化氮分子    C．H2SO4中的“2”表示一个硫酸分子中含有2个氢元素    D．Al2（O4）3中化学式上方的“一2”表示3个硫酸根的化合价为一2价  答案：B解析:略 同义句转换（1）An elephant is stronger than a horse.A horse is an elephant（2）Tom is very strong . He can lift the heavy box.Tom is the heavy box（3）I was so amazed that I couldn't say a word.I was amazed say a word（4）Kate works harder than meI work Kate（5）I have about thirty books . Mary has about fifty booksMary has books me