CPU执行算术运算或者逻辑运算时，算术逻辑运算部件（ALU）将计算结果保存在（）中。
A.累加器AC
B.程序计数器PC
C.指令寄存器IR
D.地址寄存器AR
参考答案：A
解析：
本题考查计算机系统硬件方面的基础知识。
CPU中包含多种寄存器，其中程序计数器PC保存要执行的指令的地址，当程序顺序执行时，每取出一条指令，PC内容自动增加一个值，指向下一条要取的指令。当控制流出现转移时，则将转移地址送入PC，然后由PC指向新的指令地址。指令寄存器IR存放正在执行的指令。
地址寄存器AR用来保存当前CPU所访问的内存单元的地址。由于在内存和CPU之间存在着操作速度上的差别，因此必须使用地址寄存器来保存地址信息，直到内存的读/写操作完成为止。
累加器AC在运算过程中暂时存放被操作数和中间运算结果，不能用于长时间地保存一个数据。
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| Is language, like food, a basic human need without which a child at a critical period of life can be 1 and damaged? Judging from an experiment in the thirteenth century, it may be. Hoping to discover what language a child would speak if a baby heard no mother 2 , the experimenter told the nurses to keep silent. All the 3 died before the first year. But clearly there was more than lack of language here. What was missing was good mothering. Without good mothering, in the first year of life 4 , the capacity to survive is seriously affected. Today no such severe lack exists as that ordered by the experimenter. 5 , some children are still backward in speaking. Most often the reason for this is that the mother is 6 to the signals of the infant, whose brain is programmed to learn language rapidly. If these sensitive periods are neglected, the ideal time for 7 skills passes and they might never be learned so easily again. A bird learns to sing and to fly rapidly at right time, but the process is slow and hard once the 8 stage has passed. Experts suggest that speech stages are reached in a fixed sequence and at a 9 age, but there are cases where speech has started 10 in a child who eventually turns out to be of high IQ. At twelve weeks a baby smiles and makes vowel-like sounds; at twelve months he can speak simple words and understand simple 11 ; at eighteen months he has a vocabulary of three to fifty words. At three he knows about 1,000 words which he can put into sentences, and at four his language differs from that of his parents in style 12 grammar. Recent evidence suggests that an infant is born with the 13 to speak. What is special about man's brain, compared with that of the monkey, is the complex system which enables a child to 14 the sight and feel of, say, a toy-bear with the sound pattern "toy - bear". And even more 15 is the young brain's ability to pick out an order in language from the mixture of sound around him, to analyse, to combine and recombine the parts of a language in new ways. | ||||
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