[填空题]

The atmosphere is a mixture of several gases. There are about ten chemical elements which remain permanently in gaseous form in the atmosphere Under all natural conditions. Of these permanent gases, oxygen makes up about 21 per cent and nitrogen about 78 per cent. 41) _____________________________________________.The amount of water vapor, and its variations in amount and distribution is of extraordinary importance in weather changes. Atmospheric gases hold in suspension great quantities of dust, pollen, smoke, and other impurities which are always present in considerable, but variable amounts.
The atmosphere has no definite upper limits but gradually thins until it becomes imperceptible(难以察觉的). Until recently it was assumed that the air above the first few miles gradually grew thinner and colder at a constant rate. 42)_____________________________________________. Recent studies of the upper atmosphere, currently being conducted by earth satellites and missile probing(探查

[填空题]

The atmosphere is a mixture of several gases. There are about ten chemical elements which remain permanently in gaseous form in the atmosphere Under all natural conditions. Of these permanent gases, oxygen makes up about 21 per cent and nitrogen about 78 per cent. 41) _____________________________________________.The amount of water vapor, and its variations in amount and distribution is of extraordinary importance in weather changes. Atmospheric gases hold in suspension great quantities of dust, pollen, smoke, and other impurities which are always present in considerable, but variable amounts.
The atmosphere has no definite upper limits but gradually thins until it becomes imperceptible(难以察觉的). Until recently it was assumed that the air above the first few miles gradually grew thinner and colder at a constant rate. 42)_____________________________________________. Recent studies of the upper atmosphere, currently being conducted by earth satellites and missile probing(探查

[简答题]PassageB By2050,forthefirsttimeinhistory,therewillbemorepeopleintheworldoverage65thanunderage14.TheGlobalCityIndicatorsFacility(GCIF)inTorontohaspartneredwithPhilipsintheNetherlandstoreleaseanewreportonCitiesandAging.Thispolicysnapshotoutlinesstrategiesforaddressingtheneedsofouragingurbanpopulation,andshowshowinternationallystandardizedindicatorsof“age‐friendlycities”canbeusedtobenchmarkandpredictscenariosforbetter‐informeddecision‐making.Thereport,andGCIF’songoingresearch,willinformandguidecityleadersonhowtobetterconfrontthechallengesassociatedwithanagingpopulation. Globally,peopleovertheageof65willincreaseby183percentby2050.InpartsofAfrica,theincreaseisastartling366percent.Atthesametime,urbanizationhasbecomeadefiningphenomenonofthe21stcentury,anditisprojectedthat70percentoftheworld’spopulationwillliveincities.Giventhesetwocriticalpopulationshifts,thisrapidlyagingworldsignifiesrapidlyagingcities. Municipalpolicydecisionsarebecomingincreasinglyvitaltothestateofthewor
A. A．we should take the accessibility of care facilities and health services into consideration.
B．the government has to prolong the working time of the old who are expected to retire later.
C．the young have many more old people to take care of and their happiness index will decrease.
D．the developing speed of our economy will slow down for the lack of efficient labors.

[填空题]A
What is to happen about transport Evidently there are huge and important changes in prospect. A decade or so from now, there will have been yet another transformation in the way in which people and their goods are moved from place to place. Old techniques are being faced with attenuation or even extinction, sometimes because better methods of traveling have come along but sometimes simply because the old methods have become intolerable.
B
The development of recent decades most obviously likely to be continued is the tendency for alternative methods of traveling to coexist, and so to offer potential travelers a choice. Within large cities, underground transport is usually an alternative to several ways of traveling on the surface. Roads, railways and airlines are in competition, and there are still people who cross the North Atlantic by sea. (Most freight goes that way, of course.)
C
Oil tankers could decisively affect the pattern of petroleum dis