Passage 8

    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 tiny particles or atoms and that these must be completely mixed together in the __2__. This threw a new light in the laws of definite proportions. It was __3_ necessary to suppose that the atoms could combines into small groups of uniform __5__ and so form more complex substance; thus the mystery of this law was __5__ . Dalton suggested, for example, that carbon monoxide __6__ formed by the one with one pairing of atoms of carbon and oxygen, __7_ carbon dioxide results from a single atom of carbon uniting with two atoms __8__ oxygen. Assuming this to be true, then the definite proportions of Prout´s law would naturally __9_ the relative weights of the many __10__ kinds of atoms.

    1. A. gases B. pieces C. things D. gas

    2. A. sky B. atmosphere C. oxygen D. environment

    3. A. only B. too C. that D. extremely

    4. A. construct B. structure C. piece D. feature

    5. A. solved B. discovered C. broke D. told

    6. A. must B. been C. were D. is

    7. A. while B. when C. therefore D. also

    8. A. from B. in C. of D. for

    9. A. describe B. unit C. mix D. reveal

    10.A.different B. usual C. important D. chemical

    1.【答案】A

    【解析】根據(jù)上文中的heavier and lighter gases可以確定, 本空中應填入“組成的氣體”，即constituent gases。

    2.【答案】B

    【解析】sky意為“天空”，atmosphere意為“大氣”, oxygen意為“氧氣”, environment意為“環(huán)境”,只有B項正確。

    3.【答案】A

    【解析】only necessary的意思是“僅僅是必要”。故A正確。

    4.【答案】B

    【解析】根據(jù)句子意思判斷,這里需要“結(jié)構(gòu)”這個詞，而B合乎題意。

    5.【答案】A

    【解析】solve相當于find a solution or an answer to, 意為“解決”、“解開”,如: solve a problem (a puzzle, a mystery)；discover相當于find something existing but not known before, 意為“發(fā)現(xiàn)”,如: discover a place (a fact, the truth)。因此應選A。

    6.【答案】D

    【解析】因為是表一般規(guī)律，又是單數(shù)，所以用is這個詞。

    7.【答案】A

    【解析】while表示對比。如：Some substances are soluble, while others are not.一些物質(zhì)是可溶的，而另一些物質(zhì)是不可溶的。

    8.【答案】C

    【解析】of表示“含量，分量”。

    9.【答案】B

    【解析】describe意為“描述”；unite意為“結(jié)合，合并”；mix意為“(不同的東西)混合在一起”，如：mix flour and water；reveal意為“揭露，揭示”

    10.【答案】A