如果VHFNAV控制面板显示的频率是108.1MHZ，此时按下该面板的测试电门，以下说法正确的是（）
A. 对VOR进行测试
B. 对DME进行测试
C. 对ILS进行测试
D. 以上都不对
Large volumes of carbon dioxide are safe and effective for fighting fires in enclosed spaces，such as in a pumproom，provided that the（）.
A. persons in the space wear gas masks
B. persons in the space wear damp cloths over their mouths and nostrils
C. ventilation system is secured and all persons leave the space
D. ventilation system is kept operating
电力市场管理制度对各单位的用电设备和管理范围作出明确界定。
A. 正确
B. 错误
Which two statements about the implementation of WLAN QoS are true？（）
A. The 802.11e standard is the IEEE 802.11 OoS WLAN standard.
B. The Wi-Fi Multimedia （WMM） standard decreases the eight priority levels to four access categories.
C. The Wi-Fi Multimedia （WMM） standard is a Wi-Fi Alliance standard that increases the four priority levels to eight access categories.
D. The Wi-Fi Multimedia （WMM） standard is an IEEE standard that increases the four priority levels to eight access categories.
E. Wireless 802.11 deploys Distributed Coordination Function （DCF）， carrier sense multiple access with collision detection （CSMA/CD）， interframe spacing， and random wait timers to avoid collisions.
F. Wireless OoS designs and implementations commonly use Layer 3 differentiated services code point （DSCP） or Layer 2 802.1 p to ensure priority
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