题目

You should keep in mind ______ you should behave while travelling abroad.    A. that              B. what             C. how              D. where 答案：C下列各有关的叙述，反映物质的物理性质的是（　　）A．加油站内严禁烟火，严禁接打手机B．相同条件下，铁的密度比镁的密度大C．在潮湿的空气中铁易生锈D．绿色的碱式碳酸铜受热变成黑色