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选择题
本大题共12小题，每小题2分。在每小题所给出的四个选项中，只有一项是符合题目要求的。
下列哪个选项属于条件反射( )
D.信号反射

A.眨眼反射
B.吸吮反射
C.防御反射

【参考答案】

D
解析：此题要注意区分无条件反射与条件反射的不同。
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The making of classifications by literary historiabs can be a somewhat risky enterprisE.When Black poets are discussed separately as a group, for instance, the extent to which their work reflects the development of poetry in general should not be forgotten, or a distortion of literary history may result. This reminder is particularly relevant in an assessment of the differences between Black poets at the turn of last century (1900-1909) and those of the generation of the 1920s. These differences include the bolder and more forthright speech of the later generation and its technical inventiveness. It should be remembered, though, that comparable differences also existed for similar generations of White poets.When poets of the 1910s and 1920s are considered together, however, the distinctions that literary historians might make between 'conservative' and 'experimental' would be of little significance in a discussion of Black poets, although these remain helpful classification for White poets of these decades. ①Certainly differences can be noted between 'conservative' Black poets such as Countee Cullen ,and Cluade McKay and 'experimental' ones such as Jean Toomer and Langston Hughes. But Black poets were not battling over old or new styles; rather, one accomplished Black poet was ready to welcome another. whatever his or her style, for what mattered was racial pridE.However, in the 1920s Black poets did debate with specifically racial subjects. They asked whether they should only write about Black experience for a Black audience or whether such demands were restrictivE.It may be said, though, that virtually all those poets wrote their best poems when they spoke out of racial feeling, race being, as James Johnson rightly put it 'inevitably the thing the Negro poet knows best'.At the turn of the 20th century, by contrast, most Black poets generally wrote in the conventional manner of the age and expressed noble, if vague, emotions in their poetry. These poets were not unusually gifted, though Roscoe Jamision and G. M. McClellen may be mentioned as exceptions. They chose not to write in dialect, which, as Sterling Brown has suggested, 'meant a rejection of stereotypes of Nero lifE.' and they refused to write only about racial subjects. This refusal had both a positive and a negative consequencE.As Brown observes, 'Valuably insisting that Negro poets should not be confined to issues of race, these poets committed (an) error they refused to look into their hearts and writE.' These are important insights, but one must stress that this refusal to look within was also typical of most White poets of the United States at the timE.They, too, often turned from their own experience and consequently produced not very memorable poems about vague topics, such as the peace of naturE.What is the author's attitude toward the classification as a technique in literary history'?A.SarcastiC.B.Indifferent.C.Cautious.D.Critical.
A.When
B.
C.
D.
E.'
F.'
G.
What
H.SarcastiC.
B.Indifferent.
C.Cautious.
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In their world of darkness, it would seem likely that some of the animals might have become blind, as has happened to some cave faunA.So, indeed, many of them have, compensating for the lack of eyes with marvelously developed feelers and long, slender fins and processes with which they grope their way, like so many blind men with canes, their whole knowledge of friends, enemies, or food coming to them through the sense of touch.The last traces of plant life are left behind in the thin upper layer of water for no plant can live below about 600 feet even in very clear water, and few find enough sunlight for their food-manufacturing activities below 200 feet. Since no animal can make its own food, the creatures of the deeper waters live a strange, almost parasitic existence of utter dependence on the upper layers. These hungry carnivores prey fiercely and relentlessly upon each other, yet the whole community is ultimately dependent upon the slow rain of descending food particles from abovE.The components of this never-ending rain are the dead and dying plants and animals from the surface, or from one of the intermediate layers. For each of the horizontal zones or communities of the sea that lie between the surface and the sea bottom, the food supply is different and in general poorer than for the layer abovE.Pressure, darkness, and silence are the conditions of life in the deep seA.But we know now that the conception of the sea as a silent place is wholly falsE.Wide experience with hydrophones and other listening devices for the detection of submarines has proved that, around the shore lines of much of the world, there is the extraordinary uproar produced by fishes, shrimps, porpoises and probably other forms not yet identifieD.There has been little investigation as yet of sound in the deep, offshore areas, but when the crew of the Atlantis lowered a hydrophone into deep water off Bermuda, they recorded strange mewing sounds, shrieks, and ghostly moans, the sources of which have not been traceD.But fish of shallower zones have been captured and confined in aquaria, where their voices have been recorded for comparison with sounds heard at sea, and in many cases satisfactory identification can be madE.During the Second World War the hydrophone network set up by the United States Navy to protect the entrance to Chesapeake Bay was temporarily made useless when, in the spring of 1942, the speakers at the surface began to give forth, every evening, a sound described as being like 'a pneumatic drill tearing up pavement'. The extraneous noises that came over the hydrophones completely masked the sounds of the passage of ships. Eventually it was discovered that the sounds were the voices of fish known as croakers, Which in the spring move into Chesapeake Bay from the offshore wintering grounds. As soon as the noise had been identified and analyzed, it was possible to screen it out with an electric filter, so that once more only the sounds of ships came thorugh the speakers.Many underwater animals cannot see because ______.A.the lack of light has gradually eliminated their capacity to seeB.they use sound waves instead of light to navigate in the darknessC.they have learned to survive without seeing their enemies or their preyD.their sense of touch has eliminated their need to see
A.B.
C.
D.
Many
E.
A.the
F.they
G.they
H.their
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