企业必须在其产品或者包装、( )标注生产许可证标志和编号。
参考答案：说明书上
The old lady ______ great pain when her only son was killed in a traffic accident.[ ]
A. took
B. suffered
C. suffered at
D. stood
现实世界中客观存在并能相互区别的事物称为( )。
A．物体
B．物质
C．实体
D．个体
