单选题
The economic costs of noise are several. Airports are currently operating at less than 27 because of noise regulations which restrict their hours of operation. For instance, at Washington's National Airport no jet traffic is allowed from 11 p.m. to 7 a.m. Other airports restrict the use ofcertain runway. One estimate is that noise 28 reduce possible airport use by 20 percent. The 29 cargo trade is especially affected by night restrictions. In the case of airports, jet engines may be 30 to reduce their noise level, or insulation from air traffic noise may be provided by the purchase of land around airports or the insulation of buildings. One estimate is that $5.7 billion would be required to 31 all existing jet engines with noise control devices. However, 32 the current state of the art, even taking this step will not reduce noise levels at all points to 33 values. Some combination of methods is probably necessary. If all aircraft were made quieter by existing methods, there would be a number of economic benefits. An increase in airport capacity would 34 . Property values near airports might rise. Transportation costs to and from airports could be reduced since the airports now could be located closer to population center. Much research still needs to be done on the economic 35 of noise reduction and noise effects. Although some of the effects of noise pollution are known, more must be discovered about its effects on health, productivity, property values and the quality of life. 36 , the cost of noise pollution control to the economy as a whole needs to be investigated. A.identification B.equip C.profitable D.capacity E.pollution F.restrictions G.transformed H.significant I.Furthermore J.acceptable K.modified L.Accordingly M.considering N.occur O.aspects
【答案解析】空格前为动词短语be required to,空格后为名词短语all existing jet engines,可知此处应填入一个及物动词的动词原形。备选的动词原形有equip和occur两项,但occur只能作不及物动词。equip sth. with sth. 意为“为……装备……”,符合句意:“据估计,人们可能需要花57亿美元为所有现有的喷气式引擎装上噪音控制设备”。
问答题
【正确答案】M
【答案解析】分析可知,句子主干为taking this step will not reduce noise levels。而空格所在的分句没有引导词,也没有谓语动词,只能是非谓语动词短语作主句的状语。因此,此处应填入动词的非谓语形式,即动词的现在分词、过去分词或不定式。符合语法条件的有transformed和considering两项。transformed意为“转变”,considering意为“考虑到”。这句话的意思是“______当今的技术水平,即使采取了这一措施,也不能使噪音水平降低到各方面都______的数值”。对比两个选项可知,considering更符合句意。