A Cisco Aironet 1020 controller-based access point has been connected to a Catalyst 3550-24PWR Switch. However， when it is powered up， the access point fails. What has caused this problem？（） ["access point does not support 802.11h","incorrect switch power supply","switch port is not enabled","switch does not support 802.3af","access point has not been initialized with the primary controller"]
加工中心的刀具由（）管理。 ["可编程控制器","刀库","压力装置","自动解码器"]
根据土石坝施工方法的不同，可将土石坝划分为以下五种：（）、（）、（）、（）和（）。
何谓等高线？ 它有哪些特性？
若遇到大雾、暴风雨，照明不良而影响能见度，应采取的措施是（）。 ["运输设备慢速行驶","挖掘机及排土设备一定谨慎操作","应立即停止作业"]
视域
