下列电器中不能实现短路保护的是（）。
A. 熔断器
B. 过电流继电器
C. 热继电器
D. 低压断路器
ASZ－30型自动苏生器减压器内压力不大于（）MPa。
A. 0.6
B. 0.7
C. 0.8
D. 0.9
Which statement is correct regarding the operation of DHCP?（）
A DHCP client uses a ping to detect address conflicts.(ARP)
B. A DHCP server uses a gratuitous ARP to detect DHCP clients.
C. A DHCP client uses a gratuitous ARP to detect a DHCP server.
D. If an address conflict is detected, the address is removed from the pool and an administrator must resolve the conflict.
E. If an address conflict is detected, the address removed from the pool for an amount of time configurable by the administrator.
F. If an address conflict is detected, the address is removed from the pool and will not be reused until server is rebooted.
在影视作品中出现了九岁县太爷，虽为妄谈，但在中国历史上却真的出现过有12岁神童被封为上卿（在当时与丞相官职相当），那么请问这位著名的历史人物是（）
A. 欧阳修
B. 甘罗
C. 司马光
D. 方仲永
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