人教版英语必修3 unit4--5课本电子版
中国概况-厦门国家税务局
HOW LIFE BEGAN ON THE EARTH
No one
knows exactly how the earth began, as it happened
so long ago.
However, according to a widely
accepted theory, the universe began
with a
Bangthat threw matter in all directions. After
that,
atoms began to form and combine to
create stars and other bodies.
For several
billion years after the Bangthe earth was
still just a cloud of dust. What it was to
become was uncertain until
between and
billion years ago when the dust settled into a
solid
globe. The earth became so violent that
it was not clear whether the
shape would last
or not. It exploded loudly with fire and rock.
They
were in time to produce carbon, nitrogen,
water vapour and other
gases, which were to
make the earth's atmosphere. What is even more
important is that as the earth cooled down,
water began to appear on
its surface.
Water had also appeared on other planets like
Mars but, unlike
the earth, it had disappeared
later. It was not immediately obvious
that
water was to be fundamental to the development of
life. What
many scientists believe is that the
continued presence of water
allowed the earth
to dissolve harmful gases and acids into the
oceans
and seas. This produced a chain
reaction, which made it possible for
life to
develop.
Many millions of years later, the
first extremely small plants
began to appear
on the surface of the water. They multiplied and
filled the oceans and seas with oxygen, which
encouraged the later
development of early
shellfish and all sorts of fish. Next, green
plants began to grow on land. They were
followed in time by land
animals. Some were
insects. Others, called amphibians, were able to
live on land as well as in the water. Later
when the plants grew into
forests, reptiles
appeared for the first time. They produced young
generally by laying eggs. After that, some
huge animals, called
dinosaurs, developed.
They laid eggs too and existed on the earth for
more than 140 million years. However, 65
million years ago the age of
the dinosaurs
ended. Why they suddenly disappeared still remains
a
mystery. This disappearance made possible
the rise of mammals on the
earth. These
animals were different from all life forms in the
past,
because they gave birth to young
baby animals and produced milk to
feed them.
Finally about million years ago some small
clever animals, now
with hands and feet,
appeared and spread all over the earth. Thus
they have, in their turn, become the most
important animals on the
planet. But they are
not looking after the earth very well. They are
putting too much carbon dioxide into the
atmosphere, which prevents
heat from escaping
from the earth into space. As a result of this,
many scientists believe the earth may become
too hot to live on. So
whether life will
continue on the earth for millions of years to
come
will depend on whether this problem can
be solved.
A VISIT TO THE MOON
Last month
I was lucky enough to have a chance to make a trip
into
space with my friend Li Yanping, an
astronomer. We visited the moon
in our
spaceship!
Before we left, Li Yanping
explained to me that the force of
gravity
would change three times on our journey and that
the first
change would be the most powerful.
Then we were off. As the rocket
rose into the
air, we were pushed back into our seats because we
were
trying to escape the pull of the earth's
gravity. It was so hard that
we could not say
anything to each other. Gradually the weight
lessened and I was able to talk to him. is the
spaceship not
falling back to the earth On the
earth if I fall from a tree I will
fall to the
ground.
feel its pull,
at all. When we get
closer to the moon, we shall feel its gravity
pulling us, but it will not be as strong a
pull as the earth's.
cheered up immediately and
floated weightlessly around in our
spaceship
cabin watching the earth become smaller and the
moon larger.
When we got there, I wanted to
explore immediately.
said. you are right, my
mass will be less than on the earth
because
the moon is smaller and I will be able to move
more freely. I
might even grow taller if I
stay here long enough. I shall certainly
weigh
less!
But when I tried to step forward,
I found I was carried twice as far
as on the
earth and fell over.
a bit of practice now
that gravity has changed.
the hang of it and we
began to enjoy ourselves.
Leaving the moon's
gravity was not as painful as leaving the
earth's. But returning to the earth was very
frightening. We watched,
amazed as fire broke
out on the outside of the spaceship as the
earth's gravity increased. Again we were
pushed hard into our seats
as we came back to
land.
too,I know much more about gravity! Do
you think we
could visit some stars next
time
would you like to go to
CAUGHT BY
A BLACK HOLE
The spaceship warned Li Yanping
and me to be ready as we were
approaching the
what looked like an empty space. Li Yanping
said,
like a mouth always needing to be fed.
Those lights are things that
are being pulled
into it by the gravity of the hole.
interest
and amazement at the lights which seemed to be
going fainter
and fainter round the edge of
the black hole. Just then the lights on
our
spaceship went out and the computer stopped
working. What was
happening I tried to turn
the spaceship away from the hole but it
would
not move. Would it eat us too
Suddenly the
spaceship jumped and began to move round the edge
of
the hole too. The gravity of the
sick. My mouth went dry and I closed my
eyes. All the stories about
what happened when
you were caught by the gravity of a
seemed to
be true.
But then the spaceship jumped again.
This time it moved sideways
and away from the
edge of the
have seen the spaceship flying
like a bird away from the
But we felt nothing.
At last we were able to look around us. Luckily
the computer had started working again. We
realized that we had
discovered
something new about holesIf you go inside the
edge of a
if you do not, you may have an
opportunity to escape. How exciting!
Unit5
A TRIP ON
Li Daiyu and her cousin Liu
Qian were on a trip to Canada to visit
their
cousins in Montreal on the Atlantic coast. Rather
than take the
aeroplane all the way, they
decided to fly to Vancouver and then take
the
train west to east across Canada. The thought that
they could
cross the whole continent was
exciting.
Their friend, Danny Lin, was
waiting at the airport. He was going
to take
them and their baggage to catch
Canada train.
On the way to the station, he chatted about their
trip.
mountains and thousands of lakes and
forests, as well as wide rivers
and large
cities. Some people have the idea that you can
cross Canada
in less than five days, but they
forget the fact that Canada is 5,500
kilometres from coast to coast. Here in
Vancouver, you're in Canada's
warmest part.
People say it is Canada's most beautiful city
surrounded by mountains and the Pacific Ocean.
Skiing in the Rocky
Mountains and sailing in
the harbour make Vancouver one of Canada's
most popular cities to live in. Its population
is increasing rapidly.
The coast north of
Vancouver has some of the oldest and most
beautiful forests in the world. It is so wet
there that the trees are
extremely tall, some
measuring over 90 metres.
That afternoon
aboard the train, the cousins settled down in
their seats. Earlier that day, when they
crossed the Rocky Mountains,
they managed to
catch sight of some mountain goats and even a
grizzly
bear and an eagle. Their next stop was
Calgary, which is famous for
the Calgary
Stampede. Cowboys from all over the world come to
compete
in the Stampede. Many of them have a
gift for riding wild horses and
can win
thousands of dollars in prizes.
After two
days' travel, the girls began to realize that
Canada is
quite empty. At school, they had
learned that most Canadians live
within
a few hundred kilometres of the USA border, and
Canada's
population is only slightly over
thirty million, but now they were
amazed to
see such an empty country. They went through a
wheat-
growing province and saw farms that
covered thousands of acres. After
dinner, they
were back in an urban area, the busy port city of
Thunder Bay at the top of the Great Lakes. The
girls were surprised
at the fact that ocean
ships can sail up the Great Lakes. Because of
the Great Lakes, they learned, Canada has more
fresh water than any
other country in the
world. In fact, it has one-third of the world's
total fresh water, and much of it is in the
Great Lakes.
That night as they slept, the
train rushed across the top of Lake
Superior,
through the great forests and southward towards
Toronto.
“THE TURE NORTH” FROM TORONTO TO
MONTREAL
The next morning the bushes and maple
trees outside their windows
were red, gold and
orange, and there was frost on the ground,
confirming that fall had arrived in Canada.
Around noon they arrived in Toronto, the
biggest and most wealthy
city in Canada. They
were not leaving for Montreal until later, so
they went on a tour of the city. They went up
the tall CN Tower and
looked across the lake.
In the distance, they could see the misty
cloud that rose from the great Niagara Falls,
which is on the south
side of the lake. The
water flows into the Niagara River and over the
falls on its way to the sea.
They saw the
covered stadium, home of several famous basketball
teams. As they walked north from the harbour
area, Li Daiyu said,
Fei, one of my mother's
old schoolmates, lives here. I should
phone
her from a telephone booth.
They met Lin Fei
around dusk in downtown Chinatown, one of the
three in Toronto. Over dinner at a restaurant
called The Pink Pearl,
the cousins chatted
with Lin Fei, who had moved to Canada many years
earlier. can get good Cantonese food here,Lin
Fei told them,
most of the Chinese people here
come from South China,
especially Hong Kong.
It's too bad you can't go as far as Ottawa,
Canada's capital. It's approximately
four hundred kilometres
northeast of Toronto,
so it would take too long.
The train left late
that night and arrived in Montreal at dawn
the
next morning. At the station, people everywhere
were speaking
French. There were signs and ads
in French, but some of them had
English words
in smaller letters. don't leave until this
evening,
the spent the afternoon in lovely
shops and visiting
artists in their workplaces
beside the water. As they sat in a buffet
restaurant looking over the broad St Lawrence
River, a young man sat
down with them.
my
name is Henri. I'm a student at the university
nearby,
told him they were on a train trip
across Canada and that they had
only one day
in Montreal.
city with wonderful restaurants
and clubs. Most of us speak both
English and
French, but the city has French culture and
traditions.
We love good coffee, good bread
and good music.
That night as the train was
speeding along the St Lawrence River
toward
the Gulf of St Lawrence and down to the distant
east coast,
the cousins dreamed of French
restaurants and red maple leaves.
IQALUIT--
THE FROZEN TOWN
The reporter, Beth Allen,
arrived in a northern community called
Iqaluit
in Nunavut .Nunavut was created in 1999 as a
special area for
Inuit people. Its name means
the farthest northeastern area of Canada,
north of the Arctic Circle,
and is very cold -
the average winter temperature in Nunavut is 35
degrees below zero.
Beth said,
Maybe
there is a dog sled that can take me into town.
The quiet man who had been on the plane with
her said,
you into town, but I don't have a
dog sled. Most people only use the
dogs for
competitions. Why are you visiting Iqaluit
Beth answered, writing a story for my
newspaper about
Iqaluit - we'd like to
advertise it as a holiday place, but I think
it's too cold.
The man laughed.
think
it's too far north here for holidays but more and
more tourists
are coming. They like ice
fishing and photographing polar bears. I
stay
as far away from polar bears as possible. I like
my warm office
and my warm house.
Beth
asked,
for a living I thought you lived in ice
houses.
he hunted in winter, but not so
many people do that now. The old men
used to
make one in a few hours. They used to live in skin
tents in
summer - the tents were easy to move
so the people could follow the
animals.
A
few minutes later they arrived in Iqaluit, a town
with a
population of 6,000, on Simon's
snowmobile. It was two o'clock in the
afternoon, but it was already dark, and all
the houses shone with
bright lights. Beth
said,
day!
Simon replied,
You should
come in June. The sun shines all night in the
north then.
That's why it's called 'The Land
of the Midnight Sun'.There were
people on the
streets and snowmobiles everywhere. There were
even a
few dog teams.