由于网络的发达,一些年轻老师经常在一些教育论坛上互通信息,下载试题,这是好的．但是对网上的试题,尤其是答案要慎重对待,仔细分析,否则,只图省事或一味相信答案就会出问题．试举一例．题目如下图所示．小明为防止家中停水而设计了一个贮水箱,当水箱中水深达到1.2m时,浮子A恰好堵住进 Due to the development of the Internet, some young teachers often exchange information on some educational forums and download test questions. This is good. However, on the Internet test questions, especially the answers should be treated carefully, careful analysis, otherwise, just to save trouble or blindly believe the answer will be a problem. Give an example. The title is as shown in the figure below. Xiao Ming designed a storage tank to prevent the water from being stopped in the home. When the water depth in the tank reached 1.2m, the float A just blocked it.