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【单选题】
We are all busy talking about and using the Internet, but how many of us know the history of the Internet? Many people are surprised when they find that the Internet was set up in the 1960s. At that time, computers were large and expensive. Computer networks didn't work well. If one computer in the network broke down, the whole network stopped. So a new network system had to be set up. It should be good enough to be used by many different computers. If part of the network was not working, information could be sent through another part. In this way computer network system would keep on working all the time. At first the Internet was only used by the government, but in the early 1970s, universities, hospitals and banks were allowed to use it, too. However, computers were still very expensive and the Internet was difficult to use. By the start of 1990s, computers became cheaper and easier to use. Scientists had also developed software that made 'surfing' the Internet easier. Today it is easy to get on-line and it is said that millions fo people use the internet every day. Sending emails is more and more popular among young people. The Internet has now become one of the most important parts of people's life. How long has the Internet been used?
A.
For about 10 years.
B.
For about 20 years.
C.
For about 40 years.
D.
For about 60 years.
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【单选题】已知图中二极管的反向击穿电压为100V,测得【图片】。保持U和R不变,温度下降10℃,I将____。【图片】
A.
为 2μA 左右
B.
为 0.5μA 左右
C.
变化不大
D.
远大于 2μA
【单选题】选择题:已知图中二极管的反向击穿电压为 100V ,测得 I = 1μA 。 当 R 从10kΩ 减小至 5kΩ 时, I 将 。
A.
为2μA 左右
B.
为0.5μA 左右
C.
变化不大
D.
远大于2μA
【单选题】已知图中二极管的反向击穿电压为100V,测得【图片】。保持U和R不变,温度下降10℃,I将____。【图片】
A.
为 2μA 左右
B.
变化不大
C.
为 0.5μA 左右
D.
远大于 2μA
【单选题】“没听一些老记者说吗,写采访稿对他们来说就是小菜一碟。”这句话的意思是什么?( )
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听一些老记者说,他们写采访稿就像做菜一样
B.
我没听老记者说过,写采访稿对他们来说很容易
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听一些老记者说,写采访稿对他们来说很容易
【单选题】已知图中二极管的反向击穿电压为100V,测得【图片】。当R从10kΩ 减小至5kΩ 时,I将____。【图片】
A.
为 0.5μA 左右
B.
远大于 2μA
C.
变化不大
D.
为 2μA 左右
【单选题】生南星能被生姜降低毒性,这种配伍关系属()
A.
相使
B.
相畏
C.
相杀
D.
相恶
E.
相反
【单选题】选择题:已知图中二极管的反向击穿电压为 100V ,测得 I = 1μA 。 保持 V 和 R 不变,温度下降10 °C , I 将 。
A.
为2μA 左右
B.
为0.5μA 左右
C.
不变化
D.
远大于2μA
【多选题】已知图中二极管的反向击穿电压为100V,测得I=1mA 。 1.当R从10 减小至5 时,I将____。 2.保持V和R不变,温度下降10°C,I将____。
A.
为2mA 左右
B.
变化不大
C.
远大于2A
D.
完全相同
E.
为0.5mA 左右
【简答题】已知图中二极管的反向击穿电压为 100V ,测得 I = 1 μ A 。 1 .当 R 从 10kΩ 减小至 5kΩ 时, I 将为 ____ 。( A . 2 μ A , B . 0.5 μ A , C .变化不大, D .大于 2 μ A ) 2 .当 V 增大到 20V 时,则 I 约为 ____ 。 ( A . 10 μ A , B . 2 μ A , C . 1 μ A , D . 0....
【单选题】已知图中二极管的反向击穿电压为 100V ,测得 I = 1 μ A 。 当 R 从 10 kΩ减小至 5 k Ω 时, I 将 ____ 。
A.
为 2 μ A 左右
B.
为 0.5 μ A 左右
C.
变化不大,
D.
远大于 2 μ A
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