全国计算机软考英语考前练习试题及解析（15）

　　In recent years, one of the more poplar topics panel discussions at computer conferences and trade { A } has been the"RISC versus CISC"debate.

　　RISC processors feature a small number of instructions that each executes in { B } machine cycle. CISC processors use complex instructions that can take several cycles to execute.

　　The RISC Versus CISC debate won't be decided by panel discussion 1 it will be won in the marketplace. And the deciding factor may have little to do with { C } of instructions and registers) and more to do with parallelism.

　　Since their conception, RISC processors have been evolving toward microparallelism, in corporating parallel-processing features { D } the processor. RISC processors feature pipelining, whereby many instructions can be decoded while one instruction executes.

　　RISC processor, however, are moving to toward pipelines for each unit of the processor.

　　CISC processors also employ pipelining. They have many interger instructions that execute in one cycle, but the varying execution times of CISC instructions { E } the effectiveness of parallelis.

　　供选择的答案

　　A～E：①union ②two ③numbers ④between ⑤limit

　　⑥contents ⑦shows ⑧one ⑨within ⑩enhance

　　【解析】

　　考试大提示参考译文：近年来，在计算机学术会议和贸易展览会上最流行的会场讨论课题之一是"RISC对CISC"的争论。

　　RISC处理器以少量指令为特征，且每条指令在一个机器周期中执行。CISC处理器使用复杂的指令，它们可能花费若干周期来执行。

　　RISC对CISC的争议将不由会场讨论来作结论，它将在市场中定胜负。并且，决定的因素也许很少取决于指令和寄存器的数目，而更多取决于并行性。

　　自从RISC概念提出后，RISC处理器正向着微并行性发展，它在处理器内部结合了并行处理的特性。RISC处理器以流水线为特点，在流水线上当一条指令执行时，许多指令能被解码。况且，RISC处理器正向着每个处理器单元多流水线发展。

　　CISC处理器也使用流水线。它们有许多在一个周期中执行的整数指令，但是CISC指令变化的执行时间限制了并行性的效率。

　　【答案】A：⑦ B：⑧ C：③ D：⑨ E：⑤