相电压是（）V ["380V","220V"]
Examine the description of the EMPLOYEES table: EMP_ID NUMBER(4) NOT NULL LAST_NAME VARCHAR2(30) NOT NULL FIRST_NAME VARCHAR2(30) DEPT_ID NUMBER(2) Which statement produces the number of different departments that have employees with last name Smith?（） ["SELECT COUNT(*) FROM employees WHERE last_name='Smith';","SELECT COUNT(dept_id) FROM employees WHERE last_name='Smith';","SELECT DISTINCT(COUNT(dept_id)) FROM employees WHERE last_name='Smith';","SELECT COUNT(DISTINCT dept_id) FROM employees WHERE last_name='Smith';","SELECT UNIQUE(dept_id) FROM employees WHERE last_name='Smith'"]
下列哪项工作不属于IT服务连续性的职责（） ["拟定保护某IT服务的可能措施","决定某IT服务对业务的关键级别","对某IT服务的恢复进行计划测试","识别某IT服务的风险"]
Your company includes mobile computer users who frequently work offline. You are planning to deploy Windows 7 by using an image. You have the following requirements： Provide access to all applications when mobile computer users first start their computers. Minimize network and local storage requirements. Provide language-pack support based on the geographic location of the user. You need to ensure that your image-creation strategy meets the requirements. What should you do？（） ["Create a single thin image for all computers.","Create a single hybrid image for all computers.","Create one thin image for the mobile computers. Create one thick image for all other computers.","Create one thick image for the mobile computers. Create one thin image for all other computers."]
煤电钻的工作电压是（）V。 ["220","110","127","380"]
简述使用DataReader获取数据的步骤。
