PZ型智能电源屏，C级防雷一般设于交流接触器前级，而D级防雷设于接触器（）。
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攀岩保护器材必须通过安全认证，其中CE是指（）。
A. 国际标准
B. 欧盟标准
C. 欧洲标准
停车时，硫铵溶液汽提塔（急冷塔上段汽提罐）的冲洗可随急冷塔上段一同进行。（）
A. 正确
B. 错误
The ARPA may swap targets when automatically tracking if two targets（）
A. are tracked on reciprocal bearings
B. are tracked at the same range
C. are tracked on the same bearing
D. pass closely to each other
If a seaplane is not used as a means of transpiration on water but is capable of being used so，it shall（）.
A. be regarded as a vessel not under command
B. be regarded as a vessel underway
C. be regarded as a vessel
D. be regarded as a sailing vessel
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