Text 3 The full influence of mechanization began shortly after 1850, when a variety of machines came rapidly into use. The introduction of these machines frequently created rebellions by workers who were fearful that the machines would rob them of their work. Patrick Bell, in Scotland, and Cyrus McCormick, in United States, produced threshing machines. Improve- meats were made in plows to compensate for different soil types. Stream power came into use in 1860s on large farms. Hay rakes, hay-loaders, and various special harvesting machines were produced, Milking machines appeared. The internal-combustion engine run by gasoline became the chief power source for the farm. In time, the number of certain farm machines that came into use skyrocketed and changed the nature of fanning. Be-tween 1940 and 1960, for example, 12 million horses and mules gave way to 5 million tractors. Tractors offer many. features that are attractive to farmers. There are, for example, numerous attach
A. mechanization is not yet introduced in some areas for economic reasons
B. human and animal labour in some areas are less expensive
C. culture is not a factor in obstacling the introduction of mechanization
D. different kinds of mechanized fanning tools are used in different cultures
Many animals have an excellent sense of smell, which they use in hunting. On the other hand, their eyesight may be poor. Dogs, for example, have poor eyesight and no color vision. They see only shades of gray. But the dog’s sense of smell is extraordinary,
The kind of dog known as Alsatian has 220 million olfactory (嗅觉) cells. Man has five million. Scientists believe that the Alsatian is one million times better than man in finding out odors.
The human sense of smell, however, is really quite good. The average human being can distinguish more than 10,000 different odors.
Your eye is a window on the nerves and blood vessels, revealing vital information about your entire body. An (1) exam starts from the outside and works in. First the ophthalmologist (眼科医生) gauges (2) with the familiar wall chart and checks visual field by moving objects in and out of (3) . A limited visual field could be the (4) of the high inner eye pressure of glaucoma(青光眼)or (5) a tumor pressing on nerves leading from the eye. The physician also checks for infection around the lashes and notes how fast the lids follow the eyes downward. Lid lag sometimes (6) thyroid disease (甲状腺疾病).
If one pupil contracts (7) the other doesn’t, the physician is (8) to the fact that (9) a tumor or stroke, perhaps, has damaged the nerves between the eye and brain. A tumor as far away (10) the lung can cause capillary problems by hitting a nerve that loops through the neck.
The white of the eye, tear ducts
A. information
B. phenomenon
C. materials
D. clues
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