剩磁年龄

But most significant of all, the jaguar has a tell-tale trademark. Instead of going for the neck or snout like most cats do, it kills with a crushing bite through the skull into the brain. This makes the jaguar prime suspect in this case. Even the gl

发表于:2018-12-03 / 阅读(79) / 评论(0) 分类 探索与发现2012年

These holes are the unmistakable hallmark of a violent death. Their shape suggest they were made by the teeth of a big cat, but which one? Today theres only one large cat in the region, the Florida panther. Though similar to the cougar at the western

发表于:2018-12-03 / 阅读(80) / 评论(0) 分类 探索与发现2012年

But how did one man and a spear produce the huge force behind this blow? The answer lies with small bits of ivory like this. They were once part of an atlatl, or spear thrower. An atlatl acts as a sort of catapult, magnifying the strength of a hunter

发表于:2018-12-03 / 阅读(96) / 评论(0) 分类 探索与发现2012年

At first sight, manatees might look like seals or dolphins. But in fact, some of their closest relatives live on land. These toenails are the giveaway, remarkably similar to those of elephants. 13,000 years ago, two other members of the elephant fami

发表于:2018-12-03 / 阅读(86) / 评论(0) 分类 探索与发现2012年

By piecing together the evidence these creatures left behind, we can build a picture of this sub-tropical corner of the continent as it was 13,000 years ago. While most of North America was still in the grip of the Big Freeze, Florida was an ice age

发表于:2018-12-03 / 阅读(89) / 评论(0) 分类 探索与发现2012年

This is Florida, a taste of the tropical, one of the world's most popular holiday destinations. Here mankind's unquenchable desire to explore and colonise reaches astronomical proportions. Eight, seven, six, five, four, three, two, one. Ignition. Lif

发表于:2018-12-03 / 阅读(71) / 评论(0) 分类 探索与发现2012年

This creates steam in oasis and a profusion of life. Today, these warm springs are a refuge for one of Florida's most tropical inhabitants. The West Indian Manatee wasn't present during the last ice age, but returned here as the waters warmed up. Eve

发表于:2018-12-03 / 阅读(90) / 评论(0) 分类 探索与发现2012年

But the glyptodont wasn't a reptile. So what was it? There is a relative of the glyptodont thats still alive today. It's the armadillo and it's a mammal, the only mammal with this kind of armor in the whole of North America. It may give us some idea

发表于:2018-12-03 / 阅读(97) / 评论(0) 分类 探索与发现2012年

Meanwhile, the ground sloth, like the mastodons, must eat most of the day to fuel its huge bulk. This may be the ice age, but by midday, temperatures soar, drawing another predator to the spring to drinkthe notorious saber-toothed cat. Most creatures

发表于:2018-12-27 / 阅读(71) / 评论(0) 分类 探索与发现2013年

This triggered other dramatic changes. As sea levels dropped, so did the inland water tables. Florida's fresh water drained away through the porous limestone rock. Pools dried up and springs diminished. Florida was on the brink of drought. And animal

发表于:2018-12-27 / 阅读(97) / 评论(0) 分类 探索与发现2013年

Could it be that drastic water shortage was the reason for the mastodons' epic migrations? Another big piece of this puzzle lies far out to sea. This is the ocean floor. But this isn't rock sprouting out at the bottom. It's wood. It's the remains of

发表于:2018-12-27 / 阅读(74) / 评论(0) 分类 探索与发现2013年

But despite their name, the mighty Everglades did not exist during the ice age. So what did pre-historic Florida look like? There is one place in northern Florida that has revealed more ice age secrets than almost anywhere else, the dark slow-moving

发表于:2018-12-27 / 阅读(74) / 评论(0) 分类 探索与发现2013年

The cold climate conifer forests of the north displaced broadleaved woodlands. Plants and animals were gradually pushed south to find a warmer climate. Florida became a refuge from the cold. Down here is where the Ice Age north met the subtropical so

发表于:2018-12-27 / 阅读(74) / 评论(0) 分类 探索与发现2013年

This is the Virginia opossum, a tree dweller found throughout many of the southern states. It's the only North American marsupial. The young are born premature and matured in the mother's pouch. And its only close relatives today are found in Central

发表于:2018-12-27 / 阅读(91) / 评论(0) 分类 探索与发现2013年

By Alan Silverman Hollywood 02 April 2006 It's back to prehistoric times for a sequel to the 2002 computer-animated family film that featured a grumpy mammoth and his traveling companions: a quick-wit

发表于:2019-01-08 / 阅读(140) / 评论(0) 分类 2006年VOA标准英语(四月)

Health Report - Fewer Children Under the Age of Five are Dying This is the VOA Special English Health Report. In recent years, the world has made progress in reducing deaths among children under the age of five. A new report says an estimated six-poi

发表于:2019-01-12 / 阅读(93) / 评论(0) 分类 2012年VOA慢速英语(九)月

Greenhouse Gas Speeded Ice Age Melting A new study in the Journal Nature provides compelling evidence that carbon dioxide was a major driver of climate change at the end of the last Ice Age. That correlation supports the prevailing scientific view th

发表于:2019-01-13 / 阅读(84) / 评论(0) 分类 VOA标准英语2012年(四月)

In the heat of the day, hunters can afford to slow down and rest in the shade. Its one of the advantages of a high-protein diet. Llamas originated here in North America are the regular visitors to the spring. The strange-looking tapir is common too.

发表于:2019-01-23 / 阅读(102) / 评论(0) 分类 探索与发现2013年

Though very powerful, shes not a sprinter and she needs to get close to her prey before she strikes. This time shes run too soon and its a fruitless chase. Then her attention is diverted to a slower-moving target, slow but not defenseless. She backs

发表于:2019-01-23 / 阅读(93) / 评论(0) 分类 探索与发现2013年

据国外媒体报道,当地时间2月14日,现年26岁的女星艾伦佩吉 Ellen Page 在拉斯维加斯的人权活动THRIVE上公开出柜,该活动旨在保障年轻同性恋团体的权益。 艾伦佩吉曾出演过《朱诺》、《盗梦

发表于:2019-02-01 / 阅读(111) / 评论(0) 分类 名人演讲视频
学英语单词
aamer
accommodation quarter
acute lupus
agema
and one's train
angdon
automated high rise storage systems
avoid someone as the plague
back spread
be worn to a frazzle
beryllium silicate
bicuspidal
boughetto
byte addressing
capsaicinoid
centre conductor
chromatin substance
compromised amplitude equalizer
cotransmission
cube ore
cut sb short
decisionist
departson
endurance distance
expansion cement
extra-uterine pregnancy
frequency pool
fundamental validity
geometric head ratio
get my feet wet
Glacier National Park
Grootegast
high-grades
hilts
hold page queue
horsepeople
incremental budgeting
industry of fine chemicals
interseeder
job action command
juggle money out of sb
karisoke
Keokuk County
Kindle Paperwhite
kittycorners
leading-notes
lineic mass
long flight
Lopp Lagoon
lost my shirt
Magdalena Peňasco
magnetic travellingcrane
maximum error
maximum melting capacity
mcleman
mean free path of gas
nuclear halogen
number storage
offset position
oil collector
open feed-water heater
orgasmical
P-blood-group system
panoramic effect
perforated screen plate
pholidichthyid
plasmophoresis
polyalphabetic substitution
possibly-intended programme
prevaricating
principal work
Prohibited Salvage
prolineas
promuslim
pseudo-gout
punch mica
pyruvates
rapid cooling installation
rational untilization of warehouse
rhinoscleroma bacillus
ringing engines
Roborowskia
rodingite
Sakha language
secondary basic accelerator
shamulle
single chip system extension register
soshi
special thrust
spread of the variables
state of the union message
Stokes transition
supporting pier
tax information authorization
tephros
total length closing error of traverse
two-card
ufcs
ventriloquists
vomiting drop
Waverley Glacier
weak jump