（）是读取（有时还可以写入）标签信息的设备可设计为手持式或固定式。
A.RFID标签
B.天线
C.信号接收器
D.阅读器
参考答案：D
前台流水
—Can you see ?
—No. Let’s go and have a look. Maybe we can help them.[ ]
A. what was happening there
B. what are they doing there
C. what are they talking there
D. what is happening there
