FDDI与Token Ring的MAC帧格式较为相似，分为两种（）。

听力原文：M: Can you buy ale some stamps and envelopes while you are in the post office?W: I don't intend to stop by the post office, but I will go to the grocery store and to the cleaners after I see the doctor.Q: Where will the woman go first?(17)A．The post office.B．The grocery stove.C．The doctor's office.D．The cleaners.

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IEEE 802.11g标准的物理层采用了扩频技术，工作在（）频段。

A．600MHz
B．800MHz
C．2.4GHz
D．19.2GHz

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