下列化学反应中，属于分解反应的是（   ）

为测定某石灰石矿中碳酸钙的含量，现称取12.5g石灰石矿样品与足量的稀盐酸反应（杂质不溶于水，也不参与反应），得到二氧化碳气体4.4g（假设生成的气体全部逸出）。请计算：该石灰石样品含CaCO₃的质量分数？

Lucy’s new job paid twice as much as she had made ____ in the restaurant.

检验乙醇中是否含有水的方法为____．

阅读短文，选择正确的答案。
    Tom went to Beijing by plane on his holiday. Every day he had fun with his parents. They went boating. They saw some elephants. They went swimming. They ate lots of delicious food. They also took many beautiful pictures. They will come back tomorrow. He enjoys his holiday.