特殊环境下。电气设备定期维护的主要内容有哪些？
How does NTP help you troubleshoot network problems?（） By calculating the time offset from the GPS or atomic clock。 By setting the router clock to the default value if the router can't connect to a time server。 By setting all network devices to the correct time。 By setting necessary time date in the timestamp informatio。
MD5的主循环有（）轮。 3。 4。 5。 8。
下列有关第一次中东战争的表述，不正确的是（）。 又称“巴勒斯坦战争”。 以色列控制了巴勒斯坦地区约4/5的土地。 近百万阿拉伯人沦为难民。 解决了以色列和阿拉伯各国的矛盾。
Which statement describes the WLCv5.2 delivery of a multicast packet from a wired PC source on VLAN_X to a respective wireless client using SSID_X, using a WLAN controller enabled for multicast?（） A packet is delivered to Cisco WLC and forwarded via multicast to all of its associated APs, and finally to all wireless clients of that Cisco WLC, via wireless multicast.。 A packet is delivered to Cisco WLC and forwarded via unicast to all of its associated APs, and finally to all wireless clients of that Cisco WLC, via wireless unicast.。 A packet is delivered to Cisco WLC and forwarded via multicast to all of its associated APs, discarded at APs without SSID_X joined wireless clients, and forwarded at APs with SSID_X joinedwireless clients via wireless multicast.。 A packet is delivered to Cisco WLC and forwarded via unicast to all of its associated APs, discarded at APs without SSID_X joined wireless clients, and forwarded at APs with SSID_X joined wireless clients via wireless multicast.。 A packet is delivered to Cisco WLC and forwarded via multicast to all of its associated APs, discarded at APs without SSID_X joined wireless clients, and forwarded at APs with SSID_X joinedwireless clients via wireless unicast.。 A packet is delivered to Cisco WLC and forwarded via unicast to all of its associated APs, discarded at APs without SSID_X joined wireless clients, and forwarded at APs with SSID_X joined wireless clients via wireless unicast.。
下列各项中属于预提所得税的征税对象的有（）。
