D.offline mode

正确答案：infrastructure mode；ad hoc mode

4、APs transmit beacon frames.An AP’s beacon frames will be transmitted over one of the（） channels.The beacon frames permit nearby wireless stations to discover and identify the AP.

A.12

B.11

C.9

D.10

正确答案：11

5、CDMA is a kind of（） protocol

A.channel division

B.taking-turns protocol

C.random access

D.none of the above

正确答案：random access