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Traditional arts of food preservation took advantage of this principle in a number of ways. The plant seeds, wheat, rye, rice, barley millet, maize, are themselves structures evolved by nature to provide stored food. The starch of their endosperm is used for the nourishment of the embryo during the time it over-winters (if it is a plant of the Temperate Zone) and until its new leaves have grown and their chlorophyll can trap energy from the sunlight to nourish the new-grown plant. The separation by threshing and winnowing is, therefore, to some degree part of a technique of food preservation.
The direct drying of other foods has also been used. Fish has been dried in many parts of the world besides Africa. Slices of dried meat are prepared by numerous races. Biltong, a form of dried meat, was a customary food for travelers. The drying of meat or fish, either in the sun or over a fire, quite apart from the degree to which it exposes the food to infection by bacteria and infestation by insects, tends also to harm its quality. Proteins are complex molecular structures which are readily disrupted. This is the reason why dried meat becomes tough and can, with some scientific justification, by likened to leather.
The technical process of drying foods indirectly by pickling them in the strong salt solutions commonly called ‘brine’ does less harm to the protein than straightforward drying, particularly if this is carried out at high temperatures. It is for this reason that many of the typical drying processes are not taken to completion. That is to say, the outer parts may be dried leaving a moist inner section. Under these circumstances, preservation is only partial. The dried food keeps longer than it would have undried but it cannot be kept indefinitely. For this reason, traditional processes are to be found in many parts of the world in which a combination of partial drying and pickling in brine is used. Quite often the drying involves exposure to smoke. Foods treated in this way are, besides fish of various sorts, bacon, hams and numerous types of sausages. (来源:英语杂志 http://www.EnglishCN.com)
11. According to the passage, insects spoil stored cereals by ________.
(A) consuming all the grain themselves
(B) generating heat and raising the surrounding temperature
(C) increasing the moisture content in the grain
(D) attacking each other for more grain
12. In speaking of the traditional methods of food preservation, the writer ________.
(A) expresses doubts about direct smoking
(B) describes salting and pickling as ineffective
(C) condemns direct drying
(D) mentions threshing and winnowing
13. Direct drying affects the quality of meat or fish because ________.
(A) it exposes them to insects
(B) it makes them hard
(C) it damages the protein
(D) it develops bacteria
14. We can learn from the passage that salting preserves food by ________.
(A) destroying the protein
(B) drawing away moisture from the food
(C) drying the food in the sun
(D) dressing the food
15. According to the passage, partial drying is useful because ________.
(A) it damages the protein less
(B) it can be combined with pickling
(C) it leaves the inside moist
(D) it makes the food soft
Questions 16—20
We are moving inexorably into the age of automation. Our aim is not to devise a mechanism which can perform a thousand different actions of any individual man but, on the contrary, one which could by a single action replace a thousand men.
Industrial automation has moved along three lines. First there is the conveyor belt system of continuous production whereby separate operations are linked into a single sequence. The goods produced by this well-established method are untouched by the worker, and the machine replaces both unskilled and semiskilled. Secondly, there is automation with feedback control of the quality of the product: here mechanisms are built into the system which can compare the output with a norm, that is, the actual product with what it is supposed to be, and then correct any shortcomings. The entire cycle of operations dispenses with human control except in so far as monitors are concerned. One or two examples of this type of automation will illustrate its immense possibilities. There is a factory in the U.S.A. which makes 1,000 million electric light bulbs a year, and the factory employs three hundred people. If the preautomation techniques were to be employed, the labour force required would leap to 25,000. A motor manufacturing company with 45,000 spare parts regulates their entire supply entirely by computer. Computers can be entrusted with most of the supervision of industrial installations, such as chemical plants or oil refineries. Thirdly, there is computer automation, for banks, accounting departments, insurance companies and the like. Here the essential features are the recording, storing, sorting and retrieval of information.
The principal merit of modern computing machines is the achievement of their vastly greater speed of operation by comparison with unaided human effort; a task which otherwise might take years, if attempted at all, now takes days or hours.
One of the most urgent problems of industrial societies rapidly introducing automation is how to fill the time that will be made free by the machines which will take over the tasks of the workers. The question is not simply of filling empty time but also of utilizing the surplus human energy that will be released. We are already seeing straws in the wind: destructive outbursts on the part of youth whose work no longer demands muscular strength. While automation will undoubtedly do away with a large number of tedious jobs, are we sure that it will not put others which are equally tedious in their place? For an enormous amount of sheer monitoring will be required. A man in an automated plant may have to sit for hours on and watching dials and taking decisive action when some signal informs him that all is not well. What meaning will his occupation bear for the worker? How will he devote his free time after a four or five hour stint of labour? Moreover, what, indeed, will be the significance for him of his leisure? If industry of the future could be purged of its monotony and meaninglessness, man would then be better equipped to use his leisure time constructively.
16. The main purpose of automation is _________.
(A) to devise the machine which could replace the semi-skilled
(B) to process information as fast as possible
(C) to develop an efficient labor-saving mechanism
(D) to make an individual man perform many different actions
17. The chief benefit of computing machines is ________.
(A) their greater speed of operation
(B) their control of the product quality
(C) their conveyor belt system of continuous production
(D) their supervision of industrial installations
18. One of the problems brought about by automation in industrial societies is _________.
(A) plenty of information
(B) surplus human energy
(C) destructive outbursts
(D) less leisure time
19. Which of the following best explains the use of ‘stint’ (para.4)?
(A) Effort.
(B) Force.
(C) Excess.
(D) Period.
20. According to the passage, which of the following statements is true?
(A) There is no automation with feedback control of the quality of the product.
(B) Computers are reliable in any supervision of industrial installations.
(C) The essential features for banks are the recording and sorting of information.
(D) Automation will undoubtedly eliminate numerous tedious jobs.
Questions 21—25
The city water pipes in Rome were usually of baked clay or lead; copper was sometimes used and also hollowed stone. For the large supply conduits leading to the city the Romans used covered channels with free water surfaces, rather than pipes. Perhaps this choice was a matter of economics, for apparently they could make lead pipes up to 15 inches in diameter. While pipes can follow the profile of undulating ground, with the pressure increasing in the lower areas, channels cannot. They must slope continuously downwards, because water in channels does not normally flow uphill; and the grade must be flat, from 1 in 60 in small channels to perhaps 1 in 3,000 in large ones, to keep the water speed down to a few feet per second. Thus the main supply channels or aqueducts had long lengths of flat grade and where they crossed depressions or valleys they were carried on elevated stone bridges in the form of tiered arches. At the beginning of the Christian era there were over 30 miles of these raised aqueducts in the 250 miles of channels and tunnels bringing water to Rome. The channels were up to 6 feet wide and 5 to 8 feet high. Sometimes channels were later added on the tops of existing ones. The remains of some of these aqueducts still grace the skyline on the outskirts of Rome and elsewhere in Europe similar ruins are found.
Brick and stone drains were constructed in various parts of Rome. The oldest existing one is the Cloaca Maxima which follows the course of an old stream. It dates back at least to the third century B.C. Later the drains were used for sewage, flushed by water from the public baths and fountains, as well as street storm run-off.
The truly surprising aspect of the achievements of all the ancient hydraulic artisans is the lack of theoretical knowledge behind their designs. Apart from the hydrostatics of Archimedes, there was no sound understanding of the most elementary principles of fluid behaviour. Sextus Frontinus, Rome’s water commissioner around A.D. 100, did not fully realize that in order to calculate the volume rate of flow in a channel it is necessary to allow for the speed of the flow as well as the area of cross-section. The Romans’ flow standard was the rate at which water would flow through a bronze pipe roughly 4/3 inch in diameter and 9 inches long. When this pipe was connected to the side of a water-supply pipe or channel as a delivery outlet, it was assumed that the outflow was at the standard rate. In fact, the amount of water delivered depended not only on the cross-sectional area of the outlet pipe but also on the speed of water flowing through it and this speed depended on the pressure in the supply pipe.
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