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Hundreds of species are declared to be extinct（A级）in the coming century．
A．die away
B．leave off
C．die out
D．leave out
答案
更多“Hundreds of species are declared to be extinct（A级）in the coming century． A．di”相关的问题
第1题
Hundreds of species are declared to be extinct in the coming century.
A．die away
B．leave off
C．die out
D．leave out
第2题
Hundreds of species are declared to be extinct in the coming century.
A. die away
B. leave off
C. die out
D. leave out
第3题
Hundreds of species are declared to be extinet（A级）in the toming Ceiltury．
A．die away
B．1cave 0ff
C．die 0ut
D．leave out
第4题
Hundreds of species are declared to be extinct（A级）in the coming century．
A．die away
B．leave off
C．die out
D．1eave out
第5题
Lichens are a partnership of two plants — fungi and algae. The lichen body is made up of a network of fungal strands. In the upper layers of these grow groups of algae. The two organisms live together to the benefit of both, a relationship known as symbiosis. The fungi provide support, absorb water, and shelter the tender algae from direct sunlight. The algae carry on photosynthesis and provide the fungi with food. The algae can live independently and are recognizable as a species that grows alone. The fungi, on the other hand, cannot live apart from their partners. They can be placed in known classes of fungi but are unlike any species that lives independently.
So definite are the form, color, and characteristics of these double organisms that for hundreds of years, they were classified as one. More than 15,000 "species" were named. If these organisms are classified as separate species, it is difficult to fit them into the existing system of classification. But if they are classified separately, these species of fungi seem rather strange. Lichens are a splendid example of the difficulties faced by taxonomists in classifying species.
Lichens may NOT grow ______ .
A．in the tropical woods
B．on the ceilings of city buildings
C．on rocks in hot springs
D．in dry desserts
第6题
1.In prehistoric times people（）.
A、ate much more than we do today
B、lived mainly on plant food
C、had a wide-ranging diet
D、were more fussy about what they ate
2.The specialization of food was started by（）.
A、the emergence of supermarkets
B、the rise of agriculture
C、the rich countries
D、the modern shops
3.According to the passage, people in the West today survive on（）.
A、carrots and tomatoes
B、several thousand types of plants and cereals
C、a very small number of cultivated foods
D、special species planted one thousand years ago
4.The conclusion seems to be that we（）.
A、could make use of more natural species
B、don't cultivate the right kind of food
C、produce more food than we need
D、cultivate too many different species
5.Most of us have come to expect（）.
A、no variation in our diet
B、a reduction in food supplies
C、a specialist diet
D、food conforming to a set standard
第7题
听力原文： Welcome to East Timor, one of the world's newest countries, and for the intrepid few, an emerging tourism destination with unspoiled natural beauty.
Hundreds of fish species have been recorded in East Timor's waters, a diversity that's enhanced by having very deep water so close to shore. East Timor is a former war zone and lacks a lot of basic infrastructure. After East Timor's vote for independence in 1999, Indonesian militias rampaged through the island. The subsequent recovery effort has been painfully slow. There are many changes to be made if tourism run by expatriates is to boost East Timor's meager economy. The government is anxious that new tourism developments don't rain East Timor's greatest asset, its natural beauty.
So, as this new nation struggles to build its economy, it faces an age-old predicament, how to make the most of its natural assets without destroying them in the process.
What is East Timor famous for as an emerging tourism destination？
A．One of the newest countries in the world.
B．Unspoiled natural beauty.
C．Hundreds offish species.
D．A former war zone.
第8题
To lure their pollinators from afar, orchids use appropriately intriguing shapes, colors, and scents. At least 50 different aromatic compounds have been analyzed in the orchid family, each blended to attract one, or at most a few, species of insects or birds. Some orchids even change their scents to interest different insects at different times.
Once the right insect has been attracted, some orchids present all sorts of one-way obstacle courses to make sure it does not leave until pollen has been accurately placed or removed. By such ingenious adaptations to specific pollinators, orchids have avoided the hazards of rampant crossbreeding in the wild, assuring the survival of species as discrete identities. At the same time they have made themselves irresistible to collectors.
The orchid is unique because of______.
A．the habitat in which it lives
B．the structure of its blossom
C．the variety of products that can be made from it
D．the length of its life
第9题
听力原文： The vast oceans of the world are dark, deep and mysterious places where eyesight counts for little as soon as you venture very far beneath the surface.
For humans, who live in a world dominated by visual stimuli, to exist in such conditions would be impossible. But for whales and dolphins that live in the ocean or, in the case of a few species, muddy rivers, the darkness is unimportant. What is important to them is sound.
Sound is an efficient way to transmit and sense information, especially as it travels five times faster through water than through air. If humans shout to someone, it is unlikely that they will be heard a kilometer away. But if a whale shouts in an ocean channel, another whale may hear it tens, if not hundreds, of kilometers away.
Whales and dolphins use sound in two ways: for communication and for echolocation. Dolphins and toothed whales communicate through a wide variety of high-frequency sounds.
But as well as using sounds to communicate, toothed whales and dolphins also rely on echolocation to learn about their immediate environment, including prey that might be waiting nearby. They produce intense short broad-band pulses of sound in the ultrasonic range. These clicks are brief, typically less than one millisecond long—but they are repeated many times each second.
(4)
A．Sense of sight.
B．Sense of hearing.
C．Sense of smell.
D．Sense of taste.
第10题
Computer reconstructions of ancient skulls (头骨) show that our ancestors had ears built like ours as far back as 350,000 years ago. The ears of social mammals(哺乳动物) are typically designed to recognize sounds made by fellow species members. "So, humanlike ears suggest humanlike speech", say researchers from Spain.
Anthropologists(人类学家) don't know for sure when people started talking. To get a better idea, the new study focused on a group of fossils(化石) from a place in Spain called Sima de los Huesos. The fossils belong to a species(人种) called Homo heidelbergensis. Modem people did not evolve from H. heidelbergensis, but an ancient group called Neandertals might have.
Using a computerized scanner(扫描机), the researchers measured ear structures on the remains. Then, they used information about living people to make three-dimensional (三维的)computer models of what the ancient ears looked like. Finally, they measured how sound would pass through the model ears.
The results showed that the ears could handle almost exactly the stone range of sounds that our ears can today. The researchers suggest that hearing and talking developed in a common ancestor shared by both Neandertals and modern people.
Other experts are more skeptical(怀疑的). Some studies have turned up conflicting results about the ears and vocal chords(声带) of Neandertals. And anyway, hearing could have evolved long before talking. The two don't necessarily go together.
If it's true that our ancestors could talk more than 350,000 years ago, that brings up another question. What kinds of things did they talk about？
"Social mammals" in the second paragraph means "______".
A．our ancestors
B．a kind of ancient human tribe
C．Homo heidelbergensis
D．Neandertals
