Dalton wondered why the heavier and lighter gases in theatmosphere did not separate as oil and water do.He finallyconcluded that the constituent 1 _must exist in the form of 2_particles or atoms and that these 3_ be completely mixedtogether in the 4 _.This threw a new light in 5_ laws of definiteproportions.It was 6_ necessary to suppose that the atoms 7 _combinesintossmall groups of uniform 8_ and so form morecomplex substance; 9_ the mystery of this law was 10_ .Daltonsuggested, for example, that carbon monoxide 11_ formed bythe one with one 12_ of atoms ofcarbon and oxygen, 13_ carbon dioxide results from a single 14_ of carbon uniting with twoatoms 15 _ oxygen.Assuming this to be true, 16_ the definite proportions of Prout’s law (17_ allchemical compounds the different constituents 18_ enter in unvarying proportions) wouldnaturally 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
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(yīng)填入“組成的氣體”，即constituent gases。
2.【答案】C
【解析】根據(jù)句子意思判斷,句中的詞意為微粒的意思，選項(xiàng)C.tiny合乎題意。
3.【答案】D
【解析】情態(tài)動(dòng)詞must在這里是“必定、必須”的意思。
4.【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(xiàng)正確。
5.【答案】C
【解析】這幫助解釋了大氣組成氣體的比例確定原理。因?yàn)槭翘刂高@一原理，用定冠詞the。
6.【答案】A
【解析】only necessary的意思是“僅僅是必要”。故A正確。
7.【答案】D
【解析】根據(jù)句子意思判斷, could是“能夠”的意思。
8.【答案】B
【解析】根據(jù)句子意思判斷,這里需要“結(jié)構(gòu)”這個(gè)詞，而B(niǎo)合乎題意。
9.【答案】C
【解析】but，nevertheless表示轉(zhuǎn)折意為“但是”，“然而”；thus意為“因此”，如There has been no rain.Thus, the crops are likely to suffer.一直沒(méi)有下雨，因此莊稼可能會(huì)受害。這里與上文有因果關(guān)系，故應(yīng)選C。
10.【答案】A
【解析】solve相當(dāng)于find a solution or an answer to,意為“解決”、“解開(kāi)”,如: solve a problem (a puzzle, a mystery)；discover相當(dāng)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(yīng)選A。
11.【答案】D
【解析】因?yàn)槭潜硪话阋?guī)律，又是單數(shù)，所以用is這個(gè)詞。
12.【答案】B
【解析】Pair這里是“匹配，配成雙”的意思。
13.【答案】A
【解析】while表示對(duì)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。
14.【答案】C
【解析】根據(jù)句子意思判斷, atom正確。
15.【答案】C
【解析】of表示“含量，分量”。
16.【答案】A
【解析】then的意思是next, after that。
17.【答案】D
【解析】for的意思是“對(duì)于，就……而言”。
18.【答案】C
【解析】根據(jù)句子意思判斷。
19.【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”。
20.【答案】A
【解析】根據(jù)句子意思判斷.
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
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(yīng)填入“組成的氣體”，即constituent gases。
2.【答案】C
【解析】根據(jù)句子意思判斷,句中的詞意為微粒的意思，選項(xiàng)C.tiny合乎題意。
3.【答案】D
【解析】情態(tài)動(dòng)詞must在這里是“必定、必須”的意思。
4.【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(xiàng)正確。
5.【答案】C
【解析】這幫助解釋了大氣組成氣體的比例確定原理。因?yàn)槭翘刂高@一原理，用定冠詞the。
6.【答案】A
【解析】only necessary的意思是“僅僅是必要”。故A正確。
7.【答案】D
【解析】根據(jù)句子意思判斷, could是“能夠”的意思。
8.【答案】B
【解析】根據(jù)句子意思判斷,這里需要“結(jié)構(gòu)”這個(gè)詞，而B(niǎo)合乎題意。
9.【答案】C
【解析】but，nevertheless表示轉(zhuǎn)折意為“但是”，“然而”；thus意為“因此”，如There has been no rain.Thus, the crops are likely to suffer.一直沒(méi)有下雨，因此莊稼可能會(huì)受害。這里與上文有因果關(guān)系，故應(yīng)選C。
10.【答案】A
【解析】solve相當(dāng)于find a solution or an answer to,意為“解決”、“解開(kāi)”,如: solve a problem (a puzzle, a mystery)；discover相當(dāng)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(yīng)選A。
11.【答案】D
【解析】因?yàn)槭潜硪话阋?guī)律，又是單數(shù)，所以用is這個(gè)詞。
12.【答案】B
【解析】Pair這里是“匹配，配成雙”的意思。
13.【答案】A
【解析】while表示對(duì)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。
14.【答案】C
【解析】根據(jù)句子意思判斷, atom正確。
15.【答案】C
【解析】of表示“含量，分量”。
16.【答案】A
【解析】then的意思是next, after that。
17.【答案】D
【解析】for的意思是“對(duì)于，就……而言”。
18.【答案】C
【解析】根據(jù)句子意思判斷。
19.【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”。
20.【答案】A
【解析】根據(jù)句子意思判斷.