第20题: [单项选择] Which of the following statements is NOT true A. The first cheerleader was a man named John Campbell. B. Cheerleaders’’ contests are only held at the state level. C. Before 1930 there were no women cheerleaders. D. The first cheerleading occurred in 1898. 参考答案:B 答案解析:从文中“Cheerleaders have their own contests every year at local,state and national levels.”可以得出B为不正确陈述。
第22题:[单选题] 安全用电常识是物理的一项重要内容。下列符合安全用电的是( )。 A. 用电器的金属外壳与零线相连 B. 三脚插头较长的那只脚无用,可以去掉 C. 用湿布擦台灯前,先将其插头从插座中拔出 D. 发现有人触电时,可直接用手去拉触电者 参考答案:C A、B、D项易引发触电事故;用湿布擦台灯前,先将其插头从插座中拔出,是比较稳妥的做法。故选C。