患者女，23岁。情绪差、话少、活动少一个月。精神检查发现，表情苦闷，愁眉苦脸，称对平

某同学做电学实验时，电路如图所示，已知他所用电流表的量程为0～0.6A，电压表的量程为0～3V，电源电压为6V（保持不变），滑动变阻器的最大阻值为50Ω，定值电阻 R₀为10Ω，开关S闭合后，在移动滑动变阻器的过程中，下列情况可能出现的是（   ）

A．电流表的最大示数为0.6A

B．滑动变阻器的最小功率为0 W

C．电压表的最小示数为1V

D．电阻R₀的最大功率为1.8W

从甲到乙，每小时行60千米，原路返回，每小时40千米．求往返甲乙的平均速度．

With a lot of difficult problems _________, the manager felt worried all the time.

A．settled

B．to be settled

C．settling

D．to settle

(41) is a protocol that a host uses to inform a router when it joins or leaves an Internet multicast group.
(42) is an error detection code that most data communication networks use.
(43) is an interior gateway protocol that uses a distance vector algorithm to propagate routing information.
(44) is a transfer mode in which all types of information are organized into fixed form cells on an asynchronous or non-periodic basis over a range of media.
(45) is an identifier of a web page.

A．ICMP

B．SMTP

C．IGMP

D．ARP

安全检查的内容包括（）。

A.查思想

B.查管理

C.查隐患、查整改

D.查事故处理