Soot and Snow：a Hot Combination
l New research from NASA scientists suggests emissions of black soot alter the way sunlight reflects off snow.According to a computer simulation，black soot may be responsible for 25 percent of observed global warming over the past century.
2 Soot in the higher latitudes of the Earth.where ice is more common，absorbs more of the sun's energy and warmth than an icy， white background.Dark-colored black carbon，or soot，absorbs sunlight，while lighter colored ice reflects sunlight.
3 Soot in areas with snow and ice may play all important role in climate change.Als0，if snow and ice covered areas begin melting.the warming effect increases，as the soot becomes more concentrated on the snow surface.“This provides a positive feedback，as glaciers and ice sheet smelt，they tend to get even dirtier，” said Dr.James Hansen，a researcher at NASA's Goddard Institute for Space Studies，NewYork.
4 Hansen found soot's effect on snow albedo（solar energy reflected back to space），which may be contributing to trends toward early springs in the Northern Hemisphere，such as thinning Arctic sea ice，melting glaciers and permafrost.Soot also is believed to play a role in changes in the atmosphere above the oceans and land.
5 “Black carbon reduces the amount of energy reflected by snow back into space，thus heating the snow surface more than if there were no black carbon~，”Hansen said.Soot's increased absorption of solar energy is especially effective in warming the world's climate. “This forcing is unusually effective，causing twice as much global warming as a carbon.dioxide forcing of the same magnitude，”Hansen noted.
6 Hansen cautioned.although the role of soot in altering global climate is substantial，it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century.Such gases are expected to be the largest climate forcing f10r也e rest of this century.
7 The researchers found that observed warming in the Northern Hemisphere was 1arge in the winter and spring at middle and high latitudes.These observations were consistent with the researchers' climate model simulations，which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight.
词汇：
soot n.煤烟，煤灰
emission n.释放，散发，排放
simulation v.模拟
latitude n.纬度
glacier n.冰川，冰河
albedo n.反照率
permafrost n.永冻层
forcing n.温室作用
dioxide n.二氧化物
magnitude n.量，大小
练习：
1.Paragraph 3____________
2.Paragraph 4____________
3.Paragraph 6____________
4.Paragraph 7____________
5.In the twentieth century，soot____________
6.Hansen cautioned that greenhouse gases____________
7. Black soot covered snow and ice____________
8.A soot forcing is unusually effective，which____________
第四部分：阅读理解（每题3分，共45分）
下面有3篇短文，每篇短文后有5道题，每道题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题，从4个选项中选择1个最佳答案涂在答题卡相应的位置上。
第1篇
Common-cold Sense
You can't beat it，but you don't have to join it.‘Maybe it got the name “common cold” because it's more common in winter.The fact is，though，being cold doesn't have anything to do with getting one 3.Colds are caused by the spread of rhinoviruses，and，at least SO far，medical science is better at telling you how to avoid getting one than how to get rid of one.
Children are the most common way cold viruses are spread to adults，because they have more colds than adults — an average of about eight per year.Why do kids seem SO much more easily to get colds than their parents？ Simple.They haven't had the opportunity to become immune to many cold viruses.
There are more than 1 50 different cold viruses，and you never have the same one twice.Being
infected by one makes you immune to it — but only it.
Colds are usually spread by direct contact，not sneezing or coughing.From another person's hand to your hand and then to your nose or eyes is the most common route.。The highest concentration of cold viruses anywhere is found under the thumbnails of a boy，although the viruses Can survive for hours on skin or other smooth surfaces.
Hygiene is your best defense.Wash your hands frequently.preferably with a disinfectant soap，especially when children in your household have colds.
But even careful hygiene won't ward off.every cold.So，what works when a coughing，sneezing，runny nose strikes？
The old prescription of two aspirins，lots of water，and bed rest is a good place to start.But you'11 also find some of the folk remedies…worth Wing.Hot mixtures of sugar（or honey），lemon，and water have real benefits.
词汇：
rhinovirus n.鼻病毒
virus n.病毒
immune adj.免疫的，有免疫力的
preferably adv.更可取地，更好地
disinfectant n.消毒剂，杀菌剂
prescription n.（1）诀窍（2）处方，药方
infect vt.传染，侵染，感染
sneeze vi.打喷嚏
remedy n.治疗，治疗法，药品
thumbnail n.拇指甲
1.Accordingtothe essay，you may have a cold because
A）the weather is too cold.
B）the spread of rhinoviruses gets people infected.
C）another person's coughing passes the cold to you
D）you wash your hands too often.
2.The best way to keep yourself from getting colds is
A）to keep yourself clean.
B）to use a disinfectant soap.
C）to take two aspirins every day.
D）to drink lots of water.
3.Children have more colds because
A）they are usually infected about eight times each year.
B）they are not immune to many cold viruses yet.
C）they never wash their hands So that their thumbnails are dirty.
D）they don't 1ike eating lemon.
4.When you are having a cold，
A）it is always the same kind of cold that you had last time.
B）it may be the same kind of cold that you had last time.
C）it is certainly not the same kind of cold that you had last time.
D）it is probably not the same kind of cold that you had last time.
5.When one is having a cold， he may often have a11 the following symptoms EXCEPT
，2017职称英语考试模全真拟试题理工类B级第二套