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问题 单项选择题

危险化学品安全技术

萃取时溶剂的选择是萃取操作的关键，( )决定了萃取过程的危险性大小和特点。

A．萃取剂的回收程序

B．萃取的安全问题

C．萃取剂的性质

D．萃取的设备

答案

参考答案：C

单项选择题

In recent years, one of the more popular topics for panel discussions at computer conferences and trade (61) has been the "RISC versus CISC" debate.

RISC processors feature a small number of instructions that each executes in (62) 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; it will be won in the marketplace. And the deciding factor may have little to do with (63) of instructions and registers and more to do with parallelism.

Since their conception, RISC processors have been evolving toward micro parallelism, incorporating parallel-processing features (64) the processor, RISC processors feature pipelining, whereby many instructions can be decoded while one instruction executes. RISC processors, however, are moving toward pipelines for each unit of the processor.

CISC processors also employ pipelining. They have many integer instructions that execute in one cycle, but the varying execution times of CISC instructions (65) the effectiveness of parallelism.

（62）处是（）

A.union

B.twoC.numbers

D.between

E.limit

F.contents

G.shows

H.one

I.within

J.enhance
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选择题
106gNa2CO3和84gNaHCO3分别与足量的盐酸溶液反应，其中（   ）

A．Na2CO3放出的CO2多

B．NaHCO3放出的CO2多

C．Na2CO3消耗的盐酸多

D．NaHCO3消耗的盐酸多
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