2. 外语
  3. Petroleum products, such as gasoline, kerosene, home heating oil, residual fuel oil, and lubricating oils, come from one source-

Petroleum products, such as gasoline, kerosene, home heating oil, residual fuel oil, and lubricating oils, come from one source-

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问题     Petroleum products, such as gasoline, kerosene, home heating oil, residual fuel oil, and lubricating oils, come from one source-crude oil found below the earth’s【S1】______, as well as under large bodies of water, from a few hundred feet below the surface to as deep as 25,000 feet into the earth’s【S2】______. Sometimes crude oil is secured by drilling a hole through the earth, but more dry holes are drilled than those producing oils. Pressure at the source or pumping【S3】______crude oil to the surface.
    Crude oil wells flow at varying rate, from ten to thousands of barrel per hour. Petroleum【S4】______are always measured in 42-gallon barrels.
    Petroleum products vary greatly in physical appearance: thin, thick, transparent or opaque, but regardless, their chemical composition is made【S5】______of only two elements: carbon and hydrogen, which form compounds called hydrocarbons. Other chemical elements【S6】______in union with the hydrocarbons are few and reclassified as impurities. Trace elements are also found, but these are of such minute quantities that they are disregarded. The【S7】______of carbon and hydrogen forms many thousands of compounds which are possible because of the various positions and joining of these two atoms in the hydrocarbon molecule.
    The various petroleum products are【S8】______from the crude oil by heating and condensing the vapors. These products are the so called light oils, such as gasoline, kerosene, and distillate oil. The residue remaining after the light oils are distilled is known as【S9】______or residual fuel oil and is used mostly for burning under boilers. Additional complicated refining processes rearrange the chemical structure of the hydrocarbon to produce other products, some of which are used to【S10】______and increase the octane rating of various types of gasoline.
A) degrade B) refined C) up D) light
E) products F) into G) surface H) heavy
I) forces J) combination K) exterior L) found
M) upgrade N) made O) interior
【S8】
选项
答案B
解析 根据句子结构，此处应填一过去分词构成被动结构。符合该结构的有refined和made。be made from的意思是“由……构成”，be refined from的意思是“从……提炼出”，符合句意的只有refined。本句意为：各种汽油产品都是通过加热和压缩原油中的水蒸气精炼而成。
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大学英语四级

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