四级完型填空模拟训练－4

四级完型填空模拟训练－4,标签：四级完形填空真题答案,四级完形填空练习技巧,http://www.xuehuiba.com

　　Dalton wondered why the heavier and lighter gases in the atmosphere did not separate as oil and water do.He finally concluded that the constituent 　1　 must exist in the form of 　2　 particles or atoms and that these 　3　 be completely mixed together in the 　4　 .This threw a new light in 　5　 laws of definite proportions.It was 　6　 necessary to suppose that the atoms 　7　 combinesintossmall groups of uniform 　8　 and so form more complex substance; 　9　 the mystery of this law was 　10　.Dalton suggested, for example, that carbon monoxide 　11　 formed bythe one with one 　12　 of atoms of carbon and oxygen, 　13　 carbon dioxide results from a single 　14　 of carbon uniting with two atoms 　15　  oxygen.Assuming this to be true, 　16　 the definite proportions of Prout's law （　17　 all chemical compounds the different constituents 　18　 enter in unvarying proportions） would naturally 　19　 the relative weights of the many 　20　 kinds of atoms.

　　1.A.gases        B.pieces        C.things        D.gas
　　2.A.timely        B.trimmed        C.tiny        D.topical
　　3.A.ought        B.could        C.will        D.must
　　4.A.sky        B.atmosphere        C.oxygen        D.environment
　　5.A.various        B.many        C.the        D.those
　　6.A.only        B.too        C.that        D.extremely
　　7.A.should        B.were        C.get        D.could
　　8.A.construct        B.structure        C.piece        D.feature
　　9.A.but        B.also        C.thus        D.nevertheless
　　10.A.solved        B.discovered        C.broked        D.told
　　11.A.must        B.been        C.were        D.is
　　12.A.putting        B.pairing        C.placing        D.preparing
　　13.A.while        B.when        C.therefore        D.also
　　14.A.piece        B.type        C.atom        D.measure
　　15.A.from        B.in        C.of        D.for
　　16.A.then        B.so        C.by        D.that
　　17.A.from        B.in        C.to        D.for
　　18.A.are        B.wouldn't        C.always        D.never
　　19.A.describe        B.unit        C.mix        D.reveal
　　20.A.different        B.usual        C.important        D.chemical

　　【答案解析】

　　1.
　　【答案】A
　　【解析】根据上文中的heavier and lighter gases可以确定,本空中应填入“组成的气体”，即constituent gases。

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