For each blank, choose the best answer from the four choices and write down on the answer sheet.

　　(66) is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string.

　　(67) 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.

　　(68) 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.

　　(69) is a device used to connect two separate network that use different communication protocol.

　　(70) is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.

　　(66) A MD B RSA C DES D MIB

　　(67) A RTP B RTTP C FTP D NNTP

　　(68) A ADSL B FTTC C HFC D FTTH

　　(69) A Router B Gateway C Bridge D hub

　　(70) A NNI B NRZ C NAK D NVT

　　答案：(66) A (67)D (68)C(69)B(70)B