(71) is a one -way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string.
(72) is a protocol that most USENET machines now use it to allow news articles to propagate from one machine to another over a reliable connection.
(73) is an approach preferred by cable TV providers. In this solution the fiber terminates at an optoelectrical converter and the final segment is a shared coaxial cable.
(74) is a device used to connect two separate network that use different communication protocol.
(75) is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.

A. RTP B. RTTP C．FTPD. NNTP

宋朝形成了“中书主民，枢密院主兵，三司主财，各不相知”的局面，这意味着（）

A.宰相行政效率不断提高

B.专制皇权的不断加强

C.相权对君权的制约加强

D.中央对地方控制加强