【填空题】Electronic mail and filing permit a (1) to...
【填空题】Electronic mail and filing permit a (1) to compose and transmit a (2) on an office automation system. In the early 1970s, the ARPAnet community developed a number of such (3), which have been heavily used. Through standard (4) format protocols, several hundred different (5) and electronic mail interfaces are able to exchange (6) with one another. These protocols are like the (7) office's specification of how recipient and (8) addresses should appear on envelopes and which (9) are allowable for envelopes. In the electronic message world, they describe what sequences of characters are required at the beginning of a (10) to identify the sending and receiving mailboxes.