在武汉卫戍总司令部召开的作战会议上，第54军郭汝瑰参谋长说：“武汉作战应置主力于外围，首先要利用幕旱山脉和大别山脉的有利地形与敌作战，寻机予敌以沉重打击，当敌军接近武汉核心时，我长江南北的部队应适时自行撤退，凭借武汉周边的崇山峻岭之屏障，继续与敌人周旋。如此，武汉作战则可以持久，整个抗战也会因我有生力量之保全而得以持久。”其保卫武汉的战略构思是（） ["开展回避敌主力的游击战术","阻止日军对华北地区的进攻","实施以武汉为中心的阵地战","坚持以空间换时间的持久战"]
For delay sensitive traffic， what are the three best ways that are used to prevent packet loss？ （） [" Compress payload."," Use header compression."," Increase link capacity."," Use random early detection."," Guarantee bandwidth to fragile flows."," Implement network-based application recognition."]
单位句可分为两大类，即（）和（）。
HBV X区基因可编码的抗原是（） ["HBsAg","HBcAg","HBeAg","HBxAg","HBV-DNA"]
Which two statements are true about Voice over IP （VoIP） packet delivery in a digital infrastructure？ （） [" Packets can arrive out of order."," Packets must take the same path to the destination."," Once packets are received at the destination router， the router performs sampling to ensure the quality of the voice traffic."," Packets can experience varying delays across the network."," Packets containing voice samples are sequentially numbered by default， allowing for reordering upon arrival at the terminal router along the path."]
说明句中的词类活用现象
策蹇驴，囊图书，夙行失道，望尘惊悸。
