第13题:[单选题]电气隔离是指工作回路与其他回路实现电气上的隔离。其安全原理是在隔离变压器的二次侧构成了一个不接地的电网,防止在二次侧工作的人员被电击。关于电气隔离技术的说法,正确的是( )。 A. 隔离变压器一次侧应保持独立,隔离回路应与大地有连接 B. 隔离变压器二次侧线路电压高低不影响电气隔离的可靠性 C. 为防止隔离回路中各设备相线漏电,各设备金属外壳采用等电位接地 D. 隔离变压器的输入绕组与输出绕组没有电气连接,并具有双重绝缘的结构 参考答案:D
To: The department managers From: Karen Orlando Date: 6 August 2010 Subject: Purchasing office equipment
参考答案:
Memo
To: The department managers From: Karen Orlando Date: 6 August 2010 Subject: Purchasing office equipment I am writing to tell you we are going to purchase some office equipment. Would you tell me what equipment in your department needs replacing Please let me know by email by 8 August. Thank you.