多項(xiàng)選擇題

適合開通adsl業(yè)務(wù)的線路長(zhǎng)度,對(duì)于0.4mm線經(jīng)應(yīng)小于();對(duì)于0.5mm線經(jīng)應(yīng)小于().()

A.3km.
B.4.5km.
C.5km.

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