1. [单选题]The equivalents of millions of telephone ( ) are transmitted on a single fiber,thinner than a human hair.
A. calls
B. lines
C. talks
D. devices
2. [单选题]固定电信服务中的被叫集中付费业务接入号码是( )。
A. 4006
B. 400
C. 4007
D. 800
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