判断某溶液是酸性溶液的方案错误的是（　　）

   The first telephone cards, produced in 1976, were Italian. Five years later the first British card appeared, and now you can buy cards in more than a hundred countries. People usually start collecting cards because they are small and light and you do not need much space for them. It is also a cheap hobby for beginners, although for some people it becomes a serious business. In Paris, for example, there is a market where you can only buy telephone cards, and some cards cost up to ￡4,000.The first Japanese card has a value of about ￡28,000. Most people only see cards with prices like these in their collectors' magazine.

一颗自由下落的小石头，经过某点时的速度是10m/s，经过另一点时的速度是30m/s，求经过这两点的时间间隔和两点间的距离．（取g=10m/s²）

20世纪20年代，西欧出现一种新现象：刚刚从事基础科学研究的人可以从国家有关机构、学会或工业公司得到研究资助。这一现象反映出（    ）