对于安全电压额定值的选用，要求根据使用环境、人员和使用方式等因素确定。金属容器内、特别潮湿处等特别危险环境中使用的手持照明灯应采用()V特低电压。
A．6
B．12
C．24
D．36
参考答案：B
解析：
安全电压是属于兼有直接接触电击和间接接触电击防护的安全措施。其保护原理是：通过对系统中可能会作用于人体的电压进行限制，从而使触电时流过人体的电流受到抑制，将触电危险性控制在没有危险的范围内。由特低电压供电的设备属于Ⅲ类设备。
1．我国国家标准规定了对应于特低电压的系列，其额定值（工频有效值）的等级为：42V、36V、24V、12V和6V。
2．安全电压额定值的选用根据使用环境、人员和使用方式等因素确定。例如特别危险环境中使用的手持电动工具应采用42V特低电压；有电击危险环境中使用的手持照明灯和局部照明灯应采用36V或24V特低电压；金属容器内、特别潮湿处等特别危险环境中使用的手持照明灯应采用12V特低电压；水下作业等场所应采用6V特低电压。
完形填空（本题有10 小题，每小题1分，共10分） 先通读短文，掌握其大意，然后从A、B、C、D四个选项中选出一个可以填入相应空白处的最佳答案。 Sally is 96 years old. She has no sons or daughters. Her husband 1 fifteen years ago. But she didn’t move into a nursing home. She would like to 2 herself every day. Every night she spends two hours 3 kids with their math for twenty years. All kids living on her street can get her help without payment（付费）. She was a famous 4 before she retired from a middle school. She gets up early in the morning, then does sports, goes shopping or helps cleaners 5 the street. And she does these happily. When the kids come for help, she is always 6 and tries her best to help them. People asked her 7__ . She said, “ I love it, it makes me happy to help them.” She is always happy every day and always says hello to people around her 8 a smile. “I’ve decided to love everything around me. So I’m happy to do 9 . I’m thankful for those kids who come to me for help. Each kid is a 10 for me. I love each day to help them.” She said. Really, a good decision decides what a person does in life.
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