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轨道电路应能防护牵引电流的干扰，采用非工频轨道电路，与（）牵引电流区分。

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You are working in an online transaction processing （OLTP） environment. You used the FLASHBACK TABLE command to flash back the CUSTOMERS table. Before executing the FLASHBACK TABLE command， the System Change Number （SCN） was 663571. After flashing back the CUSTOMERS table， you realize that the table is not in the correct state and the resultant changes are not what you had desired. So， you need to reverse the effects of the FLASHBACK TABLE command while ensuring that： a） No other user data in the database is affected. b） The operation takes the minimum possible time. Which option would you choose？（）

A. use the ROLLBACK command with SCN 663571
B. perform Flashback Transaction Query with SCN 663571
C. execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571
D. execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571

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患者不寐，多梦，易于惊醒，胆怯心悸，倦怠气短，脉弦细，最佳治疗方剂是（）

A. 黄连阿胶汤
B. 天王补心丹
C. 安神定志丸
D. 归脾汤
E. 柴胡疏肝散

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二乙胺乙酸铜分光光度法测定水中二硫化碳中，配制二硫化碳标准使用液的方法是：取一定量二硫化碳贮备液用（）稀释为100ug/ml。

A. 无水乙醇
B. 蒸馏水
C. 乙酸铜吸收液

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音素

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