当以太网中数据传输速率提高时，帧的传输时间要求按比例缩短，这样有可能会影响到冲突检测。为了能有效地检测冲突，应该(51)。

(88)

(87)

(86)

(85)

For　each　blank,　choose　the　best　answer　from　the　four　choices　and　write　down　on　the　answer　sheet.Web　browser　is　simply　a　terminal　emulator,　designed　to　display　text　on　a　screen.　The　two　essential　differences　between　an　ordinary　terminal　emulator　and　a　Web　browser　are　that　the　browser　knows　how　to　deal　with(71),　and　that　it　has　a　mechanism　for(72)graphical　files.　Display　text,　display　graphics,　and(73)hyperlinks—there's　99　percent　of　the(74)value.　That's　not　to　say　that　the　manufacturers　didn't　go　all-out　to　attach　a　hyperactive　efflorescence　of　useless　capabilities　onto　their　browsers.　Remember　when　media　channels　in　the　browser　were　a　big　deal,　instead　of　the　clutter　you　can't　wait　to　delete　from　your　favorites　of　bookmarks　menu?　Remember　when　client-side　Java　applets　were　supposed　to　become　the　preferred(75)for　application　development?　Remember　frames　and　all　their　nasty　side　effects?

(83)

(82)

(81)

(80)

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.