题目内容

E601型蒸发器主要由蒸发桶、水圈、测针和溢流桶四个部分组成。蒸发桶是蒸发器的主体部分,用于盛装蒸发观测()。

A. 气
B. 水
C. 油
D. 土

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The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER (4) NOT NULL CUSTOMER_NAME VARCHAR2 (100) NOT NULL STREET_ADDRESS VARCHAR2 (150) CITY_ADDRESS VARHCAR2 (50) STATE_ADDRESS VARCHAR2 (50) PROVINCE_ADDRESS VARCHAR2 (50) COUNTRY_ADDRESS VARCHAR2 (50) POSTAL_CODE VARCHAR2 (12) CUSTOMER_PHONE VARCHAR2 (20) The CUSTOMER_ID column is the primary key for the table. You need to determine how dispersed your customer base is. Which expression finds the number of different countries represented in the CUSTOMERS table?()

A. COUNT(UPPER(country_address))
B. COUNT(DIFF(UPPER(country_address)))
COUNT(UNIQUE(UPPER(country_address)))
D. COUNT DISTINTC UPPER(country_address)
E. COUNT(DISTINTC (UPPER(country_address)))

宜使用具有切断直流负载能力的、不带热保护的小空气开关取代原有的直流熔断器,小空气开关的额定工作电流应按最大动态负荷电流(即保护三相同时动作、跳闸和收发信机在满功率发信的状态下)的()选用。

A. 1.0~2.0倍
B. 1.5~2.0倍
C. 2.0~2.5倍
D. 2.5~3.5倍

稳定型战略是指什么?

销售渠道有两种结构形态,分别是()商品结构形态和()商品结构形态。

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