Thanksgiving 2012 Myths and Facts （1）

Before the big dinner, debunk the myths—for starters, the first "real" U.S. Thanksgiving wasn't until the 1800s—and get to the roots of Thanksgiving 2012.

Thanksgiving Dinner: Recipe for Food Coma?

Key to any Thanksgiving Day menu are a fat turkey and cranberry sauce.

An estimated 254 million turkeys will be raised for slaughter in the U.S. during 2012, up 2 percent from 2011's total, according to the U.S. Department of Agriculture's National Agricultural Statistics Service. Last year's birds were worth about five billion dollars.

About 46 million turkeys ended up on U.S. dinner tables last Thanksgiving—or about 736 million pounds (334 million kilograms) of turkey meat, according to estimates from the National Turkey Federation.

Minnesota is the United States' top turkey-producing state, followed by North Carolina, Arkansas, Missouri, Virginia, and Indiana.

These "big six" states produce two of every three U.S.-raised birds, according to U.S. Census Bureau data.

U.S. farmers will also produce 768 million pounds (348 million kilograms) of cranberries in 2012, which, like turkeys, are native to the Americas. The top producers are Wisconsin and Massachusetts.

The U.S. will also grow 2.7 billion pounds (1.22 billion kilograms) of sweet potatoes—many in North Carolina, Mississippi, California, and Louisiana—and will produce more than 1.1 billion pounds (499 million kilograms) of pumpkins.

Illinois, California, Pennsylvania, and Ohio grow the most U.S. pumpkins.

But if you overeat at Thanksgiving dinner, there's a price to be paid for all this plenty: the Thanksgiving "food coma." The post-meal fatigue may be real, but the condition is giving turkeys a bad rap.

Contrary to myth, the amount of the organic amino acid tryptophan in most turkeys isn't responsible for drowsiness.

Instead, scientists blame booze, the sheer caloric size of an average feast, or just plain-old relaxing after stressful work schedules. 

What Was on the First Thanksgiving Menu?

Little is known about the first Thanksgiving dinner in Plimoth (also spelled Plymouth) Colony in October 1621, attended by some 50 English colonists and about 90 Wampanoag American Indian men in what is now Massachusetts.

We do know that the Wampanoag killed five deer for the feast, and that the colonists shot wild fowl—which may have been geese, ducks, or turkey. Some form, or forms, of Indian corn were also served.

But Jennifer Monac, spokesperson for the living-history museum Plimoth Plantation, said the feasters likely supplemented their venison and birds with fish, lobster, clams, nuts, and wheat flour, as well as vegetables, such as pumpkins, squashes, carrots, and peas.

"They ate seasonally," Monac said in 2009, "and this was the time of the year when they were really feasting. There were lots of vegetables around, because the harvest had been brought in."

Much of what we consider traditional Thanksgiving fare was unknown at the first Thanksgiving. Potatoes and sweet potatoes hadn't yet become staples of the English diet, for example. And cranberry sauce requires sugar—an expensive delicacy in the 1600s. Likewise, pumpkin pie went missing due to a lack of crust ingredients.

If you want to eat like a Pilgrim yourself, try some of the Plimoth Plantation's recipes, including stewed pompion (pumpkin) or traditional Wampanoag succotash. 

First Thanksgiving Not a True Thanksgiving?

Long before the first Thanksgiving, American Indian peoples, Europeans, and other cultures around the world had often celebrated the harvest season with feasts to offer thanks to higher powers for their sustenance and survival.

In 1541 Spaniard Francisco Vásquez de Coronado and his troops celebrated a "Thanksgiving" while searching for New World gold in what is now the Texas Panhandle.

Later such feasts were held by French Huguenot colonists in present-day Jacksonville, Florida (1564), by English colonists and Abnaki Indians at Maine's Kennebec River (1607), and in Jamestown, Virginia (1610), when the arrival of a food-laden ship ended a brutal famine. 

But it's the 1621 Plimoth Thanksgiving that's linked to the birth of our modern holiday. To tell the truth, though, the first "real" Thanksgiving happened two centuries later.

Everything we know about the three-day Plimoth gathering comes from a description in a letter wrote by Edward Winslow, leader of the Plimoth Colony, in 1621, Monac said. The letter had been lost for 200 years and was rediscovered in the 1800s, she added.

In 1841 Boston publisher Alexander Young printed Winslow's brief account of the feast and added his own twist, dubbing the 1621 feast the "First Thanksgiving."

In Winslow's "short letter, it was clear that [the 1621 feast] was not something that was supposed to be repeated again and again. It wasn't even a Thanksgiving, which in the 17th century was a day of fasting. It was a harvest celebration," Monac said.

But after its mid-1800s appearance, Young's designation caught on—to say the least.

U.S. President Abraham Lincoln declared Thanksgiving Day a national holiday in 1863. He was probably swayed in part by magazine editor Sarah Josepha Hale—the author of the nursery rhyme "Mary Had a Little Lamb"—who had suggested Thanksgiving become a holiday, historians say.

In 1941 President Franklin Roosevelt established the current date , the fourth Thursday of November.

debunk - 揭穿真相
coma - 昏迷
cranberry - 小红莓
slaughter - 屠宰
federation - 联邦政府
census - 统计调查，人口普查
Bureau - 事务局
fatigue - 疲劳
rap - 惩罚
amino - 氨基的
tryptophan - 色氨酸
drowsiness - 睡意
booze - 大量饮酒
sheer - 完全的，绝对的
caloric - 热量
feast - 宴会
Plymouth - 普利茅斯（五月花号终点）
fowl - 家禽
venison - 鹿肉
lobster - 龙虾
clams - 扇贝
squashes - 南瓜小果
staple - 主要产物
delicacy - 佳肴
ingredient - 食材
plantation - 农园，造林地
stew - 炖
succotash - 青玉米粒煮利马豆
sustenance - 维持生命的东西
brutal - 残酷的
famine - 粮食不足
twist - 新方案
declare - 宣布
sway - 左右，摇摆，统治

Mount Doom's Neighbor Erupts in New Zealand

A New Zealand volcano that neighbors a mountain best known as Mount Doom of the Lord of the Rings films has rumbled back to life.

Mount Tongariro, situated in a remote part of the country's North Island, erupted for five minutes on November 21, spewing clouds of ash 2.5 miles (4 kilometers) high. In August, the 6,490 foot (1,978-meter) Tongariro had erupted for the first time since 1897. 

Though the recent activity seems to have ebbed, scientists have predicted another eruption of similar size will occur in the next few weeks, according to theNew Zealand Herald.

Several flights were canceled on New Zealand's North Island. Previous eruptions—notably of Iceland's Eyjafjallajökull volcano in 2010—have crippled air travel on a global scale.

"Very often volcanic ash contains microscopic fragments of volcanic glass ...  and the turbine engines of commercial aircraft produce a level of heat sufficient to melt glass," Steven Miller, of the Cooperative Institute for Research in the Atmosphere at Colorado State University, told NASA's Earth Observatory in August.

"The ash can melt onto [airplane] turbine blades and other parts of the engine, causing damage and even engine stalls. It also presents hazards to pilot visibility, causing pits and frosting on the windshields in the same way that a sandstorm damages an automobile windshield."

rumble - 隆隆作响
situate - 位于
spew - 喷出，呕吐
ebb - 衰退
cripple - 使陷于瘫痪
microscopic - 超小的
fragment - 碎片
turbine - 涡轮机
sufficient - 充分的
blade - 刃
stall - 熄火，使熄火
hazard - 危险
frosting - 结霜

Urban Grasshoppers Sing Louder

Urban grasshoppers are changing their tune.

According to a new paper in Functional Ecology, males that dwell by busy roads boost the bass of their courtship songs to be heard above traffic.

Previous research has shown that human-made sounds affect the calls of birds, whales, and frogs. This study is the first to show that insects aren't immune.

Ecologist Ulrike Lampe and her colleagues at Bielefeld University in Germany rounded up 188 male bow-winged grasshoppers (Chorthippus biguttulus)—half from quiet places, half from roadside spots—and exposed them to a female grasshopper. When the road warriors "sang" their two-second-long courtship song by rubbing their hindlegs against their front wings, they increased the lower frequencies.

Their country cousins did not. Lampe says the bass boost helps males be heard over the din of traffic, which could be disturbing the species' call-and-response mating rites. The fact that these males sang loudly in a quiet lab environment, she adds, suggests that the change is "not a spontaneous behavioral adaptation to noise" but a long-term effect.

Grasshopper Music

Lampe doesn't know if other insect species are evolving similarly. But she suspects that other types of human-made noise—from places like construction sites, airports, and train stations—would have a similar effect on grasshoppers.

Bow-winged grasshoppers are found throughout northern and central Europe. They vary in size (from 1.5 to 2 centimeters) and color (from green and brown to red and purple). Males "sing" by rubbing their hind legs against their front wings, producing a broadband signal. Most of their song occurs in a range the human ear can't hear. 

"We can distinguish between the extremes, though," says Lampe. "If we have one grasshopper that produces songs with very high frequencies and one that produces songs with [roughly] 1 kilohertz lower frequencies, we can hear the difference."

grasshoppers - 蝗虫

tune - 歌曲，旋律；调和

dwell - 居住

boost - 增加，提高

bass - 低音

courtship - 求偶

immune - 免疫的，不受影响的

round up - 积攒，围捕

warrior - 战士，勇士

rub - 摩擦，蹭

cousin - 亲戚

din - 吵闹，喧嚣的

rite - 仪式

spontaneous - 自发的，无意识的

suspect - 怀疑

broadband - 宽带

roughly - 大概

Trees, Lithuania

Photograph by Matas Juras, My Shot

This winter has been extremely beautiful in Lithuania. It was an early morning and minus 25 degrees Celsius outside. This landscape feels out of this world, but in fact it's in the outskirts of my home city, Kaunas—just a mile away from my house. Oftentimes beauty lies just a step away from our door. But we tend to ignore it. Too often we opt to chase beauty in distant exotic locations, missing all that's around us and ignoring the adverse effects of long-haul flights.

Lithuania - 立陶宛

Celsius - 摄氏

outskirts - 郊外

oftentimes - 时常地

opt - 选择，决定

chase - 追逐，打猎

exotic - （植物等）外来的，异国情调的

adverse - 不利的，有害的，相反地

long-haul - 长距离

Could Our Sun Become a "Zombie" Star?

Like a zombie, a nearly dead star has briefly sputtered back to life—giving a rare glimpse at what may be in store for our own solar system, a new study says.

Located 5,500 light-years away, the reborn star, known as Abell 30, is at the heart of a planetary nebula—glowing shells of gas and dust cast off by a dying sunlike star. 

Using NASA's Hubble Space Telescope and Chandra X-ray Observatory to peer inside the nebula, astronomers determined that the star had made what first appeared to be its final gasp 12,500 years ago.

But further scrutiny soon revealed bizarre signs—such as spurts of helium—that Abell 30 had undergone a sudden rebirth about 800 years ago.

"Thousands of years after it had sort of quieted down, then something happened that caused it to become unstable and start throwing off more material—lots of denser blobs of star stuff we see inside the shell," said study co-author William Blair, an astronomer at John Hopkins University in Baltimore.

"The chemical composition of these knots tells us they are coming from deep within the star, indicating the [star] ... had become active once again."

But within 20 years the rapid growth stopped, and the star died—part of the normal life cycle of a star.

"Reborn" Stars Rare

Such "resurrected" stars are rare—only three have been glimpsed in the entire Milky Way, and they're hard to spot: This rebirth phenomenon only happens for a very short time at the end of the star's life.

"A lot of low-mass or sunlike stars have and will do something like this, but we don't get to see it very often, because this phase of evolution is fleeting," said Blair, whose study appeared in August in the Astrophysical Journal.

What's more, "Abell 30 is giving us a peek" into what may happen to our own sun.

Our sun should remain stable for about four to five billion years before it enters into chaotic death throes, blasting and evaporating nearby planets—including Earth. 

While the outer planets, such as Uranus and Neptune, "might survive, their atmosphere would likely get burned off," Blair said—"not a pretty time to be watching up close."

Within a few thousand years after its "death," though, the sun may also go through a brief rebirth phase, he added.

zombie - 无生气的人
sputter - 喷出，飞溅出，发噼啪声
glimpse - 一瞥
planetary - 行星的，地球的
nebula - 星云
glow - 发光，炙热
peer - 凝视，同辈
gasp - 喘息
scrutiny - 精密的调查
bizarre - 奇怪的
spurt - 喷出
undergo - 经历，忍受
dense - 浓密的
blob - 小块
knot - 硬块，绳结
resurrect - 复活
fleet - 飞逝，快速的
chaotic - 无秩序的，混沌的
throe - （临死挣扎的）痛苦，（分娩的）阵痛
blast - 摧毁，爆炸
Uranus - 天王星      Neptune - 海王星

Mount Kailash Pilgrimage, Tibet

Best For: Yogis and others seeking spiritual enlightenment

Distance: 32 miles

Legendary mountaineer Reinhold Messner was once awarded a permit to climb Kailash, considered sacred to five religions. According to Hindus, the perfect pyramid of the 22,028-foot peak is where the god Shiva sits in meditation. The mountain is also a holy place to Buddhists, Jains, the Ayyavazhi branch of Hinduism, and the ancient Bon religion of Tibet. Messner decided not to deconsecrate the summit, which has never been attained by human beings. When a Spanish team planned to climb it in 2001, Messner suggested that they go find a more difficult summit. It remains unclimbed, although in recent years the Chinese government has begun to build a road on the sacred pilgrimage path, known as the kora.

While the mountain itself is forbidden, traversing 32 miles around it is an important ritual. All this religious significance means that while Kailash is not a place for mountaineers, it does draw crowds of pilgrims seeking its powerful good grace. It’s also a first-class Himalaya trek encompassing meditation sites at waterfalls, the sacred cave of Zuthal Puk, and 18,600-foot Dolma La Pass.

When to Go: April through September. Numerous companies offer tours that deal with the logistics of getting into Tibet and driving to the base of Mount Kailash, which can be crowded with pilgrims.

Insider Tip: After you complete the kora, take a dip in nearby Lake Manasarovar. At 15,060 feet, it’s one of the highest lakes on the planet. According to Hindus, the waters purify bathers, and ablutions here complete the Kailash pilgrimage.

Yogi - 瑜伽行者
spiritual - 精神的
enlightenment - 启发，（佛教）悟
legendary - 传说的
mountaineer - 登山家，山民
Kailash - 冈仁波齐峰（大日如来道场）
award - 给与
sacred - 神圣的
Hindus - 印度教徒   Buddhist - 佛教徒   Jain - 耆那教徒
Bon - 苯教
Shiva - 湿婆
holy - 神圣的，神圣的东西/场所
deconsecrate - 使不圣洁
attain - 达成，到达
pilgrimage - 朝圣之旅，参拜圣地   pilgrim - 朝圣者，香客
traverse - 横越，横贯
ritual - （宗教等）仪式，典礼
trek - （艰苦）旅行
encompass - 围绕
logistics - 后勤，物流，组织工作
insider tip - 内部情报
take a dip - 沐浴
ablution - 斋戒沐浴

Amelia Earhart

Photograph courtesy Keystone View Company

In 1932 the National Geographic Society awarded its Special Medal to Amelia Earhart, the first woman to make a solo transatlantic crossing. After receiving the medal, Earhart humbly remarked, "My flight has added nothing to aviation. After all, literally hundreds have crossed the Atlantic by air, if those who have gone in heavier-than-air and lighter-than-air craft are counted and those who have crossed the North and South Atlantic. However, I hope that the flight has meant something to women in aviation. If it has, I shall feel it was justified; but I can't claim anything else.”

solo - 单独的

transatlantic - 横断大西洋的，大西洋对岸的，大西洋两岸国家的

humbly - 谦虚地

aviation - 飞行，航空

Postcard, Germany

Photograph by Catherine Karnow

Catherine Karnow is a San Francisco-based photographer whose work has appeared in National Geographic, National Geographic Traveler, and other publications. She has been teaching photography workshops since 1995.

Isolate the Object From the Background

Often when I’m feeling a little overwhelmed by what to shoot in places like markets or busy streets, I’ll start by shooting details. I find it meditative and relaxing to concentrate on a single object. One key to capturing details is to use a shallow depth of field to separate the object from the background. In Murnau, Germany, I loved the hand-colored postcards I saw outside a shop. By using a very shallow depth of field—an aperture of f/3.5—I was able to isolate the postcard I liked most, with its turquoise water and rowboat, from the background of the busy street. I kept in a bit of the postcard above it to make sure the viewer knows it’s on a rack and was also careful to include an out-of-focus postcard on the right to hide the thick metal pole that I knew would have drawn the eye away from my focal postcard. —Catherine Karnow

feeling a little overwhelmed - 感到不知所措

meditative - 冥想的

aperture - 开口，口径

turquoise - 青绿色的，土耳其石

rowboat - 划艇

rack - 架子，（火车上的网架）

focal - 焦点的，集中在焦点上的

Lonesome George Not the Last of His Kind, After All?

The tide may be turning for the rare subspecies of giant tortoise thought to have gone extinct when its last known member, the beloved Lonesome George, died in June.

A new study by Yale University researchers reveals that DNA from George's ancestors lives on—and that more of his kind may still be alive in a remote area of Ecuador's Galápagos Islands.

This isn't the first time Chelonoidis nigra abingdoni has been revived: The massive reptiles were last seen in 1906 and considered extinct until the 1972 discovery of Lonesome George, then around 60 years old, on Pinta Island. The population had been wiped out by human settlers, who overharvested the tortoises for meat and introduced goats and pigs that destroyed the tortoises' habitat and much of the island's vegetation.

Now, in an area known as Volcano Wolf—on the secluded northern tip of Isabela, another Galápagos island—the researchers have identified 17 hybrid descendants of C.n. abingdoni within a population of 1,667 tortoises.

Genetic testing identified three males, nine females, and five juveniles (under the age of 20) with DNA from C.n. abingdoni. The presence of juveniles suggests that purebred specimens may exist on the island too, the researchers said.

"Even the parents of some of the older individuals may still be alive today, given that tortoises live for so long and that we detected high levels of ancestry in a few of these hybrids," Yale evolutionary biologist Danielle Edwards said.

Galápagos Castaways

How did Lonesome George's relatives end up some 30 miles (50 kilometers) from Pinta Island? Edwards said ocean currents, which would have carried the tortoises to other areas, had nothing to do with it. Instead, she thinks humans likely transported the animals.

Crews on 19th-century whaling and naval vessels hunted accessible islands like Pinta for oil and meat, carrying live tortoises back to their ships.

Tortoises can survive up to 12 months without food or water because of their slow metabolisms, making the creatures a useful source of meat to stave off scurvy on long sea voyages. But during naval conflicts, the giant tortoises—which weighed between 200 and 600 pounds (90 and 270 kilograms) each—were often thrown overboard to lighten the ship's load.

That could also explain why one of the Volcano Wolf tortoises contains DNA from the tortoise species Chelonoidis elephantopus, which is native to another island, as a previous study revealed. That species is also extinct in its native habitat, Floreana Island.

Life After Extinction?

Giant tortoises are essential to the Galápagos Island ecosystem, Edwards said. They scatter soil and seeds, and their eating habits help maintain the population balance of woody vegetation and cacti. Now, scientists have another chance to save C.n. abingdoni and C. elephantopus.

With a grant from the National Geographic Society's Committee for Research and Exploration, which also helped fund the current study, the researchers plan to return to Volcano Wolf's rugged countryside to collect hybrid tortoises—and purebreds, if the team can find them—and begin a captive-breeding program. 

If all goes well, both C.n. abingdoni and C. elephantopus may someday be restored to their wild homes in the Galápagos. 

"The word 'extinction' signifies the point of no return," senior research scientist Adalgisa Caccone wrote in the team's grant proposal. "Yet new technology can sometimes provide hope in challenging the irrevocable nature of this concept."

lonesome - 寂寞的，远离的
beloved - 可爱的，被爱着的
Ecuador- 厄瓜多尔
Galápagos Islands - 加拉帕戈斯群岛（世界遗产）
revive - 复苏，使生还
secluded - 远离人群的
hybrid - 杂种，混成的
descendant - 子孙
 juvenile - 青少年，少年的
purebred - 纯种的
specimen - 标本
given that - 假定，考虑到
castaway - 弃儿，被抛弃的      cast away （抛弃，因船难漂流）
whaling - 捕鲸
naval - 海军的
metabolisms - 新陈代谢
stave off - 避免，防止
scurvy - 败血病
voyages - （乘船，飞机）旅行
scatter - 散播
cactus - 仙人掌   复数 cacti
grant - 拨款，补助金
rugged - 崎岖的
captive-breeding - 人工饲养
signify - 表示
irrevocable - 不可取消的，不可改变的

Godafoss, Iceland

A glacial torrent pours over a 40-foot-high ledge at Gođafoss, "waterfall of the gods." After the Icelandic assembly adopted Christianity in 1000, its leader threw his pagan idols into the falls. The mossy island, notes geographer Guđrún Gísladóttir, "is protected from sheep."

What Made This a Photo of the Day

One of the criteria for a Photo of the Day is whether it is an image that you want to spend time with. The crisp green of the island against the smooth expanse of flowing water is so beautiful you are in awe that this scene truly exists.  

torrent - 激流，绝大多数
pour - 注入
ledge - 架
assembly  - 会议，集会
pagan - 异教徒（的），无宗教（的）
mossy - 苔藓状的
criteria - 基准，范畴
crisp - 新鲜的
in awe - 敬畏

Climate Predictions: Worst-Case May Be Most Accurate, Study Finds

In the wake of superstorm Sandy, climate change is on a lot of people's radar. By some accounts, warmer ocean temperatures intensified the hurricane as it plowed up the Gulf Stream, and rising seas may have exacerbated flooding.

Now, a new climate-change study in the journal Science says warming is here to stay.And future warming will likely be on the high side of predictions, the researchers conclude.

Atmospheric scientists John Fasullo and Kevin Trenberth studied global humidity patterns to get at an elusive question: When atmospheric carbon dioxide (CO2) levels double—as is expected by late this century—how much warmer will it become?

Estimates of this temperature increase, called equilibrium climate sensitivity, hover around 5 degrees F (2.8 degrees Celsius) by about 2100. But predictions vary more than twofold, from 3 to 8 degrees F (1.7 to 4.4 degrees Celsius).

The difference matters because higher temperatures mean larger problems with sea level rise and extreme weather, as well as large-scale changes in ocean circulation—which could in turn mean big changes on the ground.

With a 3 degree F increase, for example, New York City would feel more like Richmond, Virginia. With an 8 degree F increase, New Yorkers would experience temperatures like those in Atlanta, Georgia.

Clouds May Hold Climate-Change Key

Since the first report on climate sensitivity in 1979, no one has been able to narrow down its range. To try to solve the mystery, Fasullo and Trenberth—both of the U.S. National Center for Atmospheric Research (NCAR) in Boulder, Colorado—looked to the skies.

Clouds are key in pinpointing the level of temperature rise expected, Fasullo said. They exert a major influence on Earth's energy budget. Since they're white, clouds reflect sunlight, cooling Earth. Depending on how high they are in the atmosphere, they can also act like a blanket, holding in heat.

Yet clouds change shape, size, and brightness quickly, making modeling them difficult. Satellite observations of clouds are sketchy, and contain errors.

To sidestep these problems, Fasullo and Trenberth decided to look instead at how clouds are made. They form from water vapor in environments of high relative humidity. Conveniently, high-quality relative humidity data is readily available from satellites.

Eye of the Coming Storm?

The team's research focused on areas in the atmosphere called dry zones.

Hovering several thousand feet above Earth's surface, in the troposphere—the part of the atmosphere where clouds can form—dry zones play a primary role in the future climate.

In the Northern Hemisphere, the dry zone occupies latitudes between 10 and 30 degrees, on the level of Venezuela and Florida, respectively.

The scientists compared the observed relative humidity in the dry zones to 16 different climate models used in the most recent study by the Intergovernmental Panel on Climate Change.

Fasullo and Trenberth found that the three models that best matched the humidity observations were the same ones that predict the hottest future, with temperatures increasing 8 degrees F before century's end. The least accurate models overpredicted relative humidity and projected lower increases in temperature.

Fasullo used the analogy of an eye: "The dry zones are like the iris of the climate system. With warming, the iris dilates, decreasing cloud cover and allowing in more heat." Models that don't provide for that expansion of the dry zone fail to accurately depict observed data, he explained.

Karen Shell, a climate scientist from Oregon State University who was not involved in the research, agreed that Fasullo and Trenberth's workaround made sense. "It's a promising technique. It's one study, but if this relationship holds up, it implies the climate sensitivity is on the higher end of the range."

Meaning hotter ...

by some accounts - 有一种说法
intensify - 加剧
plow - 劈进，犁地
Gulf Stream - 墨西哥湾暖流，由墨西哥湾北上至大西洋的暖流
exacerbate - 使恶化
atmospheric - 大气的
get at - 理解，得到，够到   I cannot get at the book on the top shelf.
                                             What are you getting at? （你想说啥？）
elusive - 难理解的，不易记住的
estimate - 推定，概算
equilibrium - 均衡
hover - 在上空停止
twofold - 两倍重的，有两部分的
relative humidity - 相对湿度
exert - 发挥，尽力
readily - 迅速地，容易地
budget - 预算
hold in - 抑制          hold in place （固定）
blanket - 毯子，像毯子一样覆盖
sidestep - 避免，回避
troposphere - 对流层
respectively - 分别
analogy - 类似
iris - 虹膜
dilate - 扩大
provide for - 提供，供养    provide for old age
workaround - 解决方法，回避方案