推理题的题干中一般含有infer, imply, most likely, least likely, probably等词，分为有共性的推理题和无共性的推理题两大类。
It should be obvious that cetaceans, whales, porpoises, and dolphins are mammals. They breathe through lungs, not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke and blowhole cannot disguise their affinities with land-dwelling mammals. However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like.
Which of the following can be inferred from paragraph 1 about early sea otters?
A. It is not difficult to imagine what they looked like.
B. There were great numbers of them.
C. They lived in the sea only.
D. They did not leave many fossil remains.
Basic to any understanding of Canada in the 20 years after the Second World War is the country’s impressive population growth….
…It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through the Western world since the time of the Industrial Revolution.
It can be inferred from the passage that before the Industrial Revolution
(A) families were larger.
(B) population statistics were unreliable.
(C) the population grew steadily.
(D) economic conditions were bad.
Accustomed though we are to speaking of the films made before 1927 as “silent”, the film has never been, in the full sense of the word, silent. From the very beginning, music was regarded as an indispensable accompaniment; when the Lumiere films were shown at the first public film exhibition in the United States in February 1896, they were accompanied by piano improvisations on popular tunes. At first, the music played bore no special relationship to the films; an accompaniment of any kind was sufficient. Within a very short time, however, the incongruity of playing lively music to a solemn film became apparent, and film pianists began to take some care in matching their pieces to the mood of the film.
What can be inferred from the passage about the majority of films made after 1927?
(A) They were truly “silent.”
(B) They were accompanied by symphonic orchestras.
(C) They incorporated the sound of the actors’ voices.
(D) They corresponded to specific musical compositions.
“…The nineteenth century brought with it a burst of new discoveries and inventions that revolutionized the candle industry and made lighting available to all. In the early-to-mid-nineteenth century, a process was developed to refine tallow (fat from animals) with alkali and sulfuric acid. The result was a product called stearin. Stearin is harder and burns longer than unrefined tallow. This breakthrough meant that it was possible to make tallow candles that would not produce the usual smoke and rancid odor. Stearins were also derived from palm oils, so vegetable waxes as well as animal fats could be used to make candles …”
Which of the following can be inferred from paragraph 1 about candles before the nineteenth century?
A. They did not smoke when they were burned.
B. They produced a pleasant odor as they burned.
C. They were not available to all.
D. They contained sulfuric acid.
A folk culture is small, isolated, cohesive, conservative, nearly self-sufficient group that is homogeneous in custom and race, with a strong family or clan structure and highly developed rituals. …Unaltered folk cultures no longer exist in industrialized countries such as the United States and Canada….
By contrast, a popular culture is a large heterogeneous group, often highly individualistic and constantly changing.
What does the author imply about the United States and Canada?
(A) They value folk cultures.
(B) They have no social classes.
(C) They have popular cultures.
(D) They do not value individualism.
Both the number and the percentage of people in the United States involved in nonagricultural pursuits expanded rapidly during the half century following the civil war, with some of the most dramatic increases occurring in the domains of transportation, manufacturing, and trade and distribution.
What can be inferred from the passage about the agricultural sector of the economy after the Civil War?
(A) New technological developments had little effect on farmers.
(B) The percentage of the total population working in agriculture declined.
(C) Many farms destroyed in the war were rebuilt after the war.
(D) Farmers achieved new prosperity because of better rural transportation.