芭比拖累药物的性质有()
A酮式和烯醇式的互变异构
B与吡啶硫酸铜试液作用显紫色
C具有解热镇痛作用
D具催眠作用
E钠盐易溶于水
参考答案:A, B, D, E
交换设备应经受住在通信导线的纵电动势(),0.5s时间以内的过电压而不降低任何部件的性能。
A.110V
B.220V
C.380V
D.650V
Do you know _______ during the coming summer holiday? [ ]
A. what will Tom do
B. what did Tom do
C. what Tom will do
D. what Tom did