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问题 多选题

2007年10月24日，“嫦娥一号”卫星顺利升空，运送卫星的火箭所使用的主要燃料是偏二甲肼（化学式为C2H8N2），下列关于偏二甲肼的说法正确的是（　　）

A．偏二甲肼分子是由碳原子、氢原子、氮分子构成的

B．偏二甲肼的相对分子质量是60

C．偏二甲肼是由C、H、N三种元素组成的

D．偏二甲肼中C、H、N三种元素的质量比是1：4：1

答案

A、分子是由原子构成的，偏二甲肼分子是由碳原子、氢原子、氮原子构成的，故选项说法错误．

B、偏二甲肼的相对分子质量是12×2+1×8+14×2=60，故选项说法正确．

C、偏二甲肼是由碳、氢、氮三种元素组成的，故选项说法正确．

D、偏二甲肼中C、H、N三种元素的质量比是（12×2）：（1×8）：（14×2）=6：2：7，故选项说法错误．

故选BC．

多项选择题

急性白血病的主要表现为（）

A.组织器官浸润

B.不同程度发热

C.早期即可出血

D.进行性贫血

E.功能性呕吐
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单项选择题

For each blank, choose the best answer from the four choices and write down on the answer sheet.

It is claimed that Al applications have moved from laboratories to the real world. However, conventional von Neumann computers are (1) for Al applications, because they are de- signed mainly for numerical processing. In a larger yon Neumann computer, there is a larger ratio of memory to processing power and consequently it is even less efficient. This (2) remains no matter how fast we make the processor because the length of the computation becomes dominated by the time required to move data between (3) and memory. This is called the yon Neumann (4) . The bigger we build the machines, the worse it gets. The way to solve the problem is to diverse from the traditional architectures and to design special ones for Al applications. In the research of future Al architectures, we can take advantages of many (5) or currently emerging concepts. in computer architecture, such as dataflow computation, stack machines, tagging, pipelining, systolic array, multiprocessing, distributed processing, database machines, and inference machines.

5（）

A．existing

B．new

C．used

D．old-fashioned
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