A.數(shù)字?jǐn)?shù)據(jù)網(wǎng) B.綜合數(shù)字網(wǎng) C.公用電話網(wǎng) D.公用數(shù)據(jù)網(wǎng)
A.移動電話網(wǎng) B.公用電話網(wǎng) C.公眾網(wǎng)路 D.國內(nèi)電報網(wǎng)絡(luò)
A.1/2 B.1/3 C.1/5 D.1/10