练题的软件_练习题-2

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Part Ⅲ Reading Tasks
True／False／Not Given Exercises
Unit2
　　When was the last time you saw a frog? Chances are, if you live in a city, you have
not seen one for some time. Even in wet areas once teeming with frogs and toads, it is
becoming less and less easy to find those slimy, hopping and sometimes poisonous
members of the animal kingdom. All over the world, and even in remote parts of Australia,
frogs are losing the ecological battle for survival, and biologists are at a loss to explain
their demise. Are amphibians simply oversensitive to changes in the ecosystem? Could it
be that their rapid decline in numbers is signaling some coming environmental disaster for us all?
　　This frightening scenario is in part the consequence of a dramatic increase over the
last quarter century in the development of once natural areas of wet marshland; home not
only to frogs but to all manner of wildlife. However, as yet, there are no obvious reasons
why certain frog species are disappearing from rainforests in Australia that have barely
been touched by human hand. The mystery is unsettling to say the least, for it is known that
amphibian species are extremely sensitive to environmental variations in temperature and
moisture levels. The danger is that planet Earth might not only lose a vital link in the
ecological food chain (frogs keep populations of otherwise pestilent insects at manageable
levels), but we might be increasing our output of air pollutants to levels that may have
already become irreversible. Frogs could be inadvertently warning us of a catastrophe.
　　An example of a species of frog that, at far as is known, has become extinct, is the
platypus frog. Like the well-known Australian mammal it was named after, it exhibited
some very strange behaviour; instead of giving birth to tadpoles in the water, it raised its

young within its stomach. The baby frogs were actually born fromout of their mother s
mouth. Discovered in 1981, less than ten years later the frog had completely vanished from
the crystal clear waters of Booloumba Creek near Queensland s Sunshine Coast.
Unfortunately, this freak of nature is not the only frog species to have been lost in Australia.
Since the 1970s, no less than eight others have suffered the same fate.
　　One theory that seems to fit the facts concerns the depletion of the ozone layer, a well
documented phenomenon which has led to a sharp increase in ultraviolet radiation levels.
The ozone layer is meant to shield the Earth from UV rays, but increased radiation may be
having a greater effect upon frog populations than previously believed. Another theory is
that worldwide temperature increases are upsetting the breeding cycles of frogs.

TRUE／FALSE／NOT GIVEN
1.Frogs are disappearing only from city areas.
2.Frogs and toads are usually poisonous.
3.Biologists are unable to explain why frogs are dying.
4.The frogs natural habitat is becoming more and more developed.
5.Attempts are being made to halt the development of wet marshland.
6.Frogs are important in the ecosystem because they control pests.
7.The platypus frog became extinct by 1991.
8.Frogs usually give birth to their young in an underwater nest.
9.Eight frog species have become extinct so far in Australia.
10.There is convincing evidence that the ozone layer is being depleted.
11.It is a fact that frogs breeding cycles are upset by worldwide in creases in temperature.

Practice 3
　　Almost everyone with or without a computer is aware of the latest technological
revolution destined to change forever the way in which humans communicate,
namely, the Information Superhighway, best exemplified by the ubiquitous
Internet. Already, millions of people around the world are linked by computer
simply by having a modem and an address on the `Net , in much the same way
that owning a telephone links us to almost anyone who pays a phone bill. In
fact, since the computer connections are made via the phone line, the Internet
can be envisaged as a network of visual telephone links. It remains to seen
in which direction the Information Superhighway is headed, but many believe
it is the educational hope of the future.
　　The World Wide Web, an enormous collection of Internet addresses or sites,
all of which can be accessed for information, has been mainly responsible for
the increase in interest in the Internet in the 1990s. Before the World Wide
Web, the `Net was comparable to an integrated collection of computerized
typewriters, but the introduction of the `Web in 1990 allowed not only text
links to be made but also graphs, images and even video.
　　A Web site consists of a `home page , the first screen of a particular site
on the computer to which you are connected, from where access can be had to
other subject related `pages (or screens) at the site and on thousands of other
computers all over the world. This is achieved by a process called `hypertext .
By clicking with a mouse device on various parts of the screen, a person
connected to the `Net can go traveling, or surfing through a of the screen,
a person connected to the `Net can go traveling, or `surfing through a web
of pages to locate whatever information is required.
　　Anyone can set up a site; promoting your club, your institution, your company s

products or simply yourself, is what the Web and the Internet is all about.
And what is more, information on the Internet is not owned or controlled by
any one organization. It is, perhaps, true to say that no one and therefore
everyone owns the `Net . Because of the relative freedom of access to
information, the Internet has often been criticised by the media as a
potentially hazardous tool in the hands of young computer users. This
perception has proved to be largely false however, and the vast majority of
users both young and old get connected with the Internet for the dual purposes
for which it was intended - discovery and delight.

TRUE／FALSE／NOT GIVEN
1.Everyone is aware of the Information Superhighway.
2.Using the Internet costs the owner of a telephone extra money.
3.Internet computer connections are made by using telephone lines.
4.The World Wide Web is a network of computerised typewriters.
5.According to the author, the Information Superhighway may be the future hope of education.
6.The process called`hypertext requires the use of a mouse device.
7.The Internet was created in the 1990s.
8.The `home page is the first screen of a `Web site on the `Net .
9.The media has often criticised the Internet because it is dangerous.
10. The latest technological revolution will change the way humans communicate.

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