●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 m

●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 the 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
（72）A．alternative
B．need
C．possibility
D．solution
（73）A．design
B．redesign
C．plan
D．build
（74）A．throwaway
B．system
C．software
D．product
（75）A．worth
B．value
C．cost
D．invaluable