阅读下面材料, 从A、B、C、D四个选项中选出最佳选项。

    Jumping rope(绳子)is a sport any student can learn to do．You can jump alone or with a friend．You can also help turn a long rope for many others to jump over．If you jump alone, you will need a short rope which should be just long enough for you．

    A rope should be turned slowly．It must also be turned high enough to let you jump safely．Turning the rope safely needs careful timing．In rope jumping, timing means turning the rope slowly enough so that you can jump over it at the right time without its hitting your feet．

  You will notice that when you jump rope, you breathe(呼吸)faster and your face has a healthy colour．But, if you jump too many times at first, you will get too tired．You must learn when to stop for rest(休息)before you jump again．As you practice, you can increase the number(次数)of times you jump without resting．

实验证明铜在低温下不能和O₂发生反应，也不能和稀硫酸共热发生反应，但工业上却是将废铜屑倒入热的稀硫酸中并不断地通入空气来制取CuSO₄溶液的．铜屑在此状态下发生的一系列化学反应的化学方程式为：　 ____，　 ____．

利用铜和浓H₂SO₄在加热条件下也能制备CuSO₄溶液，其化学方程式为： ____．以上两种方法是前者好还是后者好： ____．

原因是 ____

学生小美在“腊八节”喝了一碗腊八粥后惊奇地发现，我国的许多传统节日，都成为“舌尖上的节日”：腊八节成了“粥节”、端午节成了“粽子节”、中秋节成了“月饼节”……许多90后、00后的年轻人谈起这些传统节日，最直接的反映是能放假、有吃头。小美不禁担心，长此以往，传统节日会不会消失在历史的长河中？

请你说说，小美的担心有必要吗？