● (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 re

There is nothing in this world constant but inconstancy．--SWIFT

Project after project designs a set of algorithms and then plunges into construction of customer-deliverable software on a schedule that demands delivery of the first thing built．

In most projects,the first system built is （71） usable,It may be too slow,too big,awkward to use,or all three．There is no （72） but to start again,smarting but smarter,and build a redesigned version in which these problems are solved．The discard and （73） may be done in one lump,or it may be done piece-by-piece．But all large-system experience shows that it will be done．Where a new system concept or new technology is used,one has to build a system to throw away,for even the best planning is not so omniscient（全知的）as to get it right the first time．

The management question,therefore ,is not whether to build a pilot system and throw it away．You will do that．The only question is whether to plan in advance to build a （74）,or to promise to deliver the throwaway to customers．Seen this way,the answer is much clearer．Delivering that throwaway to customers buys time,but it does so only at the （75） of agony（极大痛苦）for the user,distraction for the builders while they do the redesign,and a bad reputation for the product that best redesign will find hard to live down．

Hence plan to throw one away;you will,anyhow．

71.()

A.almost

B.often

C.usually

D.barely

Soon, more of the information we receive via the Internet could come(71)in digital wrappers.

Wrappers are made up(72)software code that's targeted to do specific things with the data(73)within them, such as helping to define queries for search engines. They also keep(74)from(75)access to that code.

A．package

B．packaged

C．packages

D．packaging

There is nothing in this world constant butinconstancy. —SWIFT Project after project designs a set of algorithms and thenplunges into construction of customer-deliverable software on a schedule thatdemands delivery of the first thing built.?

In most projects, the first system built is（71） usable. Itmay be too slow, too big, awkward to use, or all three. There is no （72） but to startagain, smarting but smarter, and build a redesigned version in which theseproblems are solved. The discard and （73） may be done in one lump, or it may be done piece-by-piece. But alllarge-system experience shows that it will be done. Where a new system conceptor new technology is used, one has to build a system to throw away, for eventhe best planning is not so omniscient （全知的） as to get it right the first time.

The management question, therefore, is notwhether to build a pilot system and throw it away. You will do that. The onlyquestion is whether to plan in advance to build a （74） , or topromise to deliver the throwaway to customers. Seen this way, the answer ismuch clearer. Delivering that throwaway to customers buys time, but it does soonly at the （75） of agony （极大痛苦）for the user, distraction for the builders while they do theredesign, and a bad reputation for the product that the best redesign will findhard to live down.

Hence plan to throw one away; you will,anyhow.

（71）

A.almost

B.often

C.usually

D.barely