20世纪50年代,为了发挥______的效率,提出了______技术,从而发展了操作

题型:单项选择题

问题:

20世纪50年代,为了发挥______的效率,提出了______技术,从而发展了操作系统,通过它对______进行管理和调度。 ( )

A.计算机 操作系统 计算机

B.计算 并行算法

C.硬件设备 多道程序 硬软资源

D.硬件设备 晶体管 计算机

考点:计算机等级考试PC技术三级PC技术笔试
题型:单项选择题

下列叙述中,哪些是PowerBuilder 的特性 Ⅰ.将应用作为对象 Ⅱ.支持与多种数据库连接 Ⅲ.支持动态数据交换 Ⅳ.支持Web快速开发

A.仅Ⅰ和Ⅱ

B.仅Ⅱ、Ⅲ和Ⅳ

C.仅Ⅲ和Ⅳ

D.全部

题型:单项选择题

信号电路图中时间继电器符号中的数字代表()。

题型:单项选择题

阅读理解。

      Mama and Daddy loved having the family together on Christmas. They spent days making candy and

cookies, preparing gifts and decorating.

      Forty-four years together made them a great team. But with Mama's unexpected death in the spring,

we now faced our first Christmas without her. The holidays would be especially hard for Daddy. We tried

to comfort him. We would all be with him on Christmas as usual.

      On Christmas Eve a small snow turned to a heavy one, covering our yard and 150-foot driveway, as

well as the access road (干道的支路). We started cleaning, but the snow was falling faster than we could

keep up. The weatherman predicted the storm would continue through the night. Church services were also

canceled. "We'll be there as soon as possible in the morning," I told Daddy on the phone. But inside I wondered

how. 

      Early Christmas morning we began digging through stomach-high snow. We finished the driveway, but

seeing the mountains of snow on the access road, we admitted failure. As I stared at the access road, I heard

the sound of a snowblower. Lord, please help us get to Daddy today, I prayed.

      The sound of the snowblower grew louder. I looked up. There, coming straight toward us was a big

yellow machine with a huge plow (犁) effortlessly clearing a path through the snow-packed road. I stared in

disbelief. Never in our 18 years here had the snow been plowed on this road.

      The driver of the snowblower sat up straight at the wheel and was warmly dressed, collar (衣领) up, cap

down-and wings beneath his coat, I'm sure.

1. We learn from the passage that the author's parents _____. [ ]

A. separated a year ago

B. were married for forty-four years

C. like spending holidays very much

D. have prepared for this Christmas for days

2. The author started to clean the snow in order to _____. [ ]

A. go to church

B. have a clean driveway

C. go to please his father

D. send his children to school

3. Before the snowblower arrived, the author had _____. [ ]

A. decided to give up

B. stopped to have a rest

C. finished the access road

D. cleaned the snow mountains

4. In the author's eyes, the driver of the snowblower was a(n) _____. [ ]

A. angel

B. father

C. ordinary cleaner

D. hard worker

题型:单项选择题

电化学腐蚀是指金属与电解质溶液接触,发生电化学反应而引起的腐蚀.

题型:单项选择题

何谓MRSA,如何选择抗生素?

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