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【简答题】
IEEE 802.15.4 规范是一种经济、高效、低数据速率( )、工作在( )的无线技术(欧洲868MHZ,美国915MHZ), 用于个域网和对等网状网络,支持传感器、远端控制和家电自动化等,不适合传输语音,通常连接距离小于( )。
拍照语音搜题，微信中搜索"皮皮学"使用
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皮皮学刷刷变学霸
举一反三
【单选题】When Mary discovered how treacherous the streets could be, she demanded that her boys stay close to her in the church gym and youth center, and the boys were as good as gold, listening to every word s...
A.
very naughty
B.
very obedient
C.
faithful
D.
patient
【单选题】Mary could be a very attractive girl but she ______to her clothes.
A.
pays attention
B.
was paying no attention
C.
paid no attention
D.
had paid attention
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