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1、个人收集整理 仅供参考学习生活需要游戏，但不能游戏人生；生活需要歌舞，但不需醉生梦死；生活需要艺术，但不能投机取巧；生活需要勇气，但不能鲁莽蛮干；生活需要重复，但不能重蹈覆辙。 -无名 College English Practice Test 1Part I Writing (30 minutes)Directions: In this part, you are allowed 30 minutes to write a short essay entitled An Eye-witness Account of a Traffic Accident. You should write a
2、t least 150 words following the outline given below. 1车祸发生的时间及地点； 2你所见到的车祸情况； 3你对车祸原因的分析。Part Reading Comprehension (Skimming and Scanning) (15 minutes) A Brief History of ClockClocks At best, historians know that 5,000-6,000 years ago, great civilizations in the Middle East and North Africa started
3、 to examine forms of clock-making instead of working with only the monthly and annual calendar. Little is known on exactly how these forms worked or indeed the actual deconstruction of the time, but it has been suggested that the intention was to maximize time available to achieve more as the size o
4、f the population grew. Perhaps such future periods of time were intended to benefit the community by allotting specific lengths of time to tasks. Was this the beginning of the working week? Sun Clocks With the disappearance of any ancient civilization, such as the Sumerian culture, knowledge is also
5、 lost. Whilst we can only hypothesize on the reasons of why the equivalent to the modern wristwatch was never completed, we know that the ancient Egyptians were next to layout a system of dividing the day into parts, similar to hours. Obelisks (tall four-sided tapered monuments) were carefully const
6、ructed and even purposefully geographically located around 3500 BC. A shadow was east as the Sun moved across the sky by the obelisk, which it appears was then marked out in sections, allowing people to clearly see the two halves of the day. Some of the sections have also been found to indicate the
7、years longest and shortest days, which it is thought were developments added later to allow identification of other important time subdivisions. Another ancient Egyptian shadow clock or sundial has been discovered to have been in use around 1500 BC, which allowed the measuring of the passage of hour
8、s. The sections were divided into ten parts, With two twilight hours indicated, occurring in the morning and the evening. For it to work successfully then at midday or noon, the device had to be turned 180 degrees to measure the afternoon hours.Water Clocks Water clocks were among the earliest time
9、keeping devices that didnt use the observation of the celestial bodies to calculate the passage of time. The ancient Greeks, it is believed, began using water clocks around 325 BC. Most of these clocks were used to determine the hours of the night, but may have also been used during daylight. An inh
10、erent problem with the water clock was that they were not totally accurate, as the system of measurement was based on the flow of water either into, or out of, a container which had markers around the sides. Another very similar form was that of a bowl that sank during a period as it was filled of w
11、ater from a regulated flow. It is known that water clocks were common across the Middle East, and that these were still being used in North Africa during the early part of the twentieth-century.Mechanical Clocks In 1656, Christian Huygens (Dutch scientist), made the first Pendulum(钟摆) clock, with a
12、mechanism using a natural period of oscillation(振幅). Galileo Galilei is credited, in most historical books, for inventing the pendulum as early as 1582, but his design was not built before his death. Huygens clock, when built, had an error of less than only one minute a day. This was a massive leap
13、in the development of maintaining accuracy, as this had previously never been achieved. Later refinements to the pendulum clock reduced this margin of error to less than 10 seconds a day. The mechanical clock continued to develop until they achieved an accuracy of a hundredth-of- a-second a day, whe
14、n the pendulum clock became the accepted standard in most astronomical observatories.Quartz Clocks The running of a Quartz clock is based on the piezoelectric property of the quartz crystal. When an electric field is applied to a quartz crystal, it actually changes the shape of the crystal itself, I
15、f you then squeeze it or bend it, an electric field is generated. When placed in an appropriate electronic circuit, this interaction between the mechanical stress and the electrical field causes the crystal to vibrate, generating a constant electric signal which can then be used for example on an electronic clock display. The first wrist-watches that appeared in mass production used LED, Light Emitting Diode displays. By the 1970s these were to be replaced
