Predicting the future is notoriously difficult.

notoriously ^{adv.众所周知地，声名狼藉地}

• Relieving the problem of overpopulation is notoriously difficult.^{众所周知，缓解人口过剩问题非常困难。}
• Giving up a deep-seated bad habit is notoriously difficult. ^{众所周知，改掉一个根深蒂固的坏习惯非常困难。}
• The traffic congestion in Beijing is notoriously serious.^{众所周知，北京的交通拥堵问题非常严重。}

Who could have imagined, in the mid 1970s, for example, that by the end of the 20th century, computers would be as common in people's homes as TV sets?

Who could have imagined that computers would become as popular as TV? ^{句子简化（虚拟语气)表示将来的情况或变化。}
We had not imagined that computers would become popular. ^{关于过去的想象（即在某个时间点之前没有预料到）}

could have done ^{used to say that something was a possibility in the past, but did not actually happen 有可能会发生，但是并没有真的发生（可以单独出现，不用if从句）}

• I could have been killed. ^{与过去事实相反(本可能发生的，但没有发生)，经常可以单独出现，后面不需要跟If从句}
• He could have escaped, but he chose to stand and fight. 

mid ^{adj.中央的，中间的，中部的}

• from mid July to mid August
• mid-morning coffee 
• Mid-Autumn Festival ^中秋节
• a young woman in her mid-twenties 
• midsummer / midwinter ^仲夏/冬
• on Midsummer Eve ^仲夏夜

Who could have imagined, in the mid 1990s, for example, that after a mere decade, mobile phones would be as common in China as watches? ^{比方说，有谁能在 20 世纪 90 年代中期想象到，仅仅十年之后，手机在中国和手表一样常见？}

In the 1970s, computers were common enough, but only in big business, government departments and large organizations.

business ^{[C] 公司}

• They don't know how to run a business.
• The company began as a small family business.
• Owners of small businesses will be hit hardest by these tax changes. 

big business ^{n. [U] large and powerful companies in general （固定搭配，总称）大公司}

• Does big business have more control over our everyday lives than our elected governments? 
• The party receives most of its financial support from big business.

These were the so-called mainframe machines.

mainframe ^{n. 英文解释：a large powerful computer that can work very fast and that a lot of people can use at the same time 主机，大型机（main 主要的 + frame 构架、结构）}

• The network has a gateway into the hospital mainframe. ^{该网络有一个网关连接医院主机。}
• Most have slavishly copied the design of IBM's big mainframe machines. ^{绝大多数公司都一味模仿IBM大型主机的设计。}
• I downloaded the whole thing into the hospital mainframe before I left work today. ^{我今天下班前把全部内容下载到了医院的主机上。}

Mainframe computers were very large indeed , often occupying whole air-conditioned rooms, employing full-time technicians and run on specially-written software.

indeed ^{adv. used with ‘very’ and an adjective or adverb to emphasize a statement or description 的确，确实}

• Most of the essays were very good indeed. 
• Thank you very much indeed.

air-conditioned ^{adj. 装空调的}

• The building provides about 25,500 sq. ft. of air-conditioned offices. ^{这座建筑提供大约2.55万平方英尺的空调办公室。}
• The new buses are air-conditioned, comfortable and easy for elderly and disabled passengers to get on and off. ^{新的公共汽车装有空调，也很舒适，方便老人和残疾乘客上下车。}
• Cool, air-conditioned apartments became furnaces. ^{凉爽、有空调的公寓变成了火炉。}

run ^{v. if you run a machine or engine, you make it operate 操作，使机器运转}

• I often run the washing machine more than once a day. ^vt.
• Most cars run on unleaded fuel. ^vi.
• They have gathered the best statistics they can find and run them through their own computers. ^{他们已经搜集了他们所能找到的最佳数据并将其在他们自己的电脑里运行。}
• Do you want to run to Canada? ^润~

Though these large machines still exist, many of their functions have been taken over by small powerful personal computers, commonly known as PCs.

take over sth. ^{接管…，代替…}

• Military leaders took over the government. ^{政变(接管了政府)}
• Computers can thus be built to take over almost any job where a series of actions are repeated over and over again.
• I'm going to take over the company one day. ^{我总有一天会接管这家公司。}

be known as … ^被称为…

• He soon made a name for himself and came to be known to the Italians as Giovanni Acuto.