氯化钠具有面心立方结构，其晶胞分子数是（）。 ["5","6","4","3"]
以下哪些情况适合用调查分析法进行预测（） ["顾客数量有限","调查费用不高","顾客意向明确","顾客意向不轻易改变"]
行李运价率为硬座客票票价率的（）%。 ["10","5","2","1"]
社会态度
Which statement is true about IP telephony calls？（） [" A Voice over IP （VoIP） packet consists of the voice payload， IP header， TCP header， RTP header， and Layer 2 link header."," The voice carrier stream uses H323 to set up， maintain， and tear down call endpoints."," Call control signaling uses Real-Time Transport Protocol （RTP） packets that contain actual voice samples."," The sum of bandwidth necessary for each major application， including voice， video， and data， should not exceed 75 percent of the total available bandwidth for each link."]
直方图
