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科技篇
1
You
should spend about 20 minutes on Questions 1-13
which are based on the following Reading Passage.
Islands That Float
Islands
are
not
known
for
their
mobility
but,
occasionally
it
occurs.
Natural
floating
islands
have
been
recorded in many parts of
the world ( Burns et al 1985 ).
Longevity studies
in lakes
have been carried out by
Hesser, and in
rivers and the open sea by Boughey ( Smithsonian
Institute 1970). They can form in two common
ways: landslides of (usually vegetated)
peaty soils into lakes or seawater or as a
flotation of peat soils ( usually
bound
by roots of woody vegetation) after storm surges,
river floods or lake level risings.
The
capacity of the living part of a floating island
to maintain its equilibrium in the face of
destructive forces,
such as fire, wave
attack or hogging and sagging while riding sea or
swell waves is a major obstacle. In general,
ocean-going floating islands are most
likely to be short-lived; wave wash-over gradually
eliminates enough of the
island's store
of fresh water to deplete soil air and kill
vegetation around the edges which, in turn, causes
erosion
and diminishes buoyancy and
horizontal mobility.
The forces acting
on a floating island determine the speed and
direction of movement, and are very similar to
those acting on floating mobile ice
chunks during the partially open-water season (
Peterson 1965). In contrast to
such
ice
rafts,
many
floating
islands
carry
vegetation,
perhaps
including
trees
which
act
as
sails.
Burns
et
al
examined
the
forces
acting
and
concluded
that
comparatively
low
wind
velocities
are
required
to
mobilise
free-floating
islands with vegetation standing two meters or
more tall.
The
sighting
of
floating
islands
at
sea
is
a
rare
event;
such
a
thing
is
unscheduled,
shortlived
and
usually
undocumented. On July 4th, 1969, an
island some 15 meters in diameter with 10 -15
trees 10 -12 meters tall was
included
in
the
daily
notice
to
mariners
as
posing
a
shipping
navigation
hazard
between
Cuba
and
Haiti.
McWhirter described
the island as looking
was
some
earth
on
it
but
it
looked
kind
of
bushy
around
the
bottom,
like
there
was
dead
foliage,
grass-like
material or something on the island
itself. The trees were coming up out of that. It
looked like the trees came right
out of
the surface brown layer. No roots were
visible
and the parts had partially
submerged so that only the upper tree trunks were
above the water. By July 19th, no
trace
of the island was found after an intensive six
hour search.
Another
example
albeit
freshwater,
can
be
found
in
Victoria,
Australia
—
the
floating
islands
of
Pirron
Yallock. Accounts of how the floating
islands were formed have been given by local
residents. These accounts
have not been
disputed in the scientific literature. Prior to
1938, the lake was an intermittent swamp which
usually
dried out in summer. A drainage
channel had been excavated at the lowest point of
the swamp at the northern part
of its
perimeter. This is likely to have encouraged the
development or enlargement of a peat mat on the
floor of the
depression. Potatoes were
grown in the centre of the depression where the
peat rose to a slight mound. The peat
was ignited by afire in 1938, which
burned from the dry edges towards a central damp
section. A track was laid
through the
swamp last century and pavement work was carried
out in 1929/30. This causeway restricted flow
between the depression and its former
southern arm. These roadworks, plus collapse and
partial infilling of the
northern
drainage channel, created drainage conditions
conducive to a transition from swamp to permanent
lake.
The transformation from swamp to
lake was dramatic,
occurring over the
winter of 1952 when rainfall of
around
250mm
was
well
above
average.
Peat
is
very
buoyant
and
the
central
raised
section
which
had
been
isolated by the fire,
broke away from the rocky, basalt floor as the
water level rose in winter. The main island then
broke up into several smaller islands
which drifted slowly for up to 200 meters within
the confines of the lake and
ranged in
size from 2 to 30 meters in diameter. The years
immediately following experienced average or above
average rainfall and the water level
was maintained. Realignment of the highway in 1963
completely blocked the
former
southern
outlet
of
the
depression,
further
enhancing
its
ability
to
retain
water.
The
road
surface
also
provided an additional source of runoff
to the depression.
Anecdotal evidence
indicates that the islands floated uninterrupted
for 30 years, following their formation.
They generally moved between the NW and
NE sides of the lake in response to the prevailing
winds. In 1980, the
Rural
Water
Commission
issued
a
nearby
motel
a
domestic
licence
to
remove
water
from
the
lake
and
occasionally water is taken for the
purpose of firefighting. The most significant
amount taken for firefighting was
during
severe
fires
in
February
1983.
Since
then,
the
Pirron
Yallock
islands
have
ceased
to
float,
and
this
is
thought to be related to
a drop in the water level of approximately 600 mm
over the past 10 -15 years. The islands
have either run aground on the bed or
the lagoon or vegetation has attached them to the
bed.
Floating islands have attracted
attention because they are uncommon and their
behaviour has provided not
only
explanations
for
events
in
myth
and
legend
but
also
great
scope
for
discussion
and
speculation
amongst
scientific and other
observers.
Peat = a dark brown
substance that is formed by plants dying and
becoming buried
Adapted from
Peterson
Questions 1-5
Do the
following statements agree with the information
given in Reading Passage? In boxes 1 - 5 on your
answer sheet write
TRUE
if the
statement agrees with the information
FALSE
if the
statement contradicts the information
NOT GIVEN
if there is no
information on this
1. Natural floating
islands occur mostly in lakes.
2.
Floating Islands occur after a heavy storm or
landslide.
3. The details of the
floating island at sea near Cuba and Haiti were
one of many seagoing islands in that area.
4. Floating islands at sea sink because
the plants on them eventually die.
5.
Scientists and local residents agree on how the
Pirron Yallock Islands were formed.
Questions 6 ~9
Look at the
following people ( questions 6-9) and the list of
statements below.
Match each person to
the correct statement.
Write the
correct letter
A
—
H
in
boxes 6-9 on your answer sheet.
6.
Burns
7.
Peterson
8.
McWhirter
9.
Hesser
A.
compared floating islands to floating blocks of
ice
B. documented the break up of a
sea-going island
C.
floating islands last longer when confined to a
limited area
D. studied the effect of
rivers on floating islands
E. like
floating islands, floating mobile ice chunks carry
vegetation
F. even comparatively light
winds can create a floating island
G.
recorded the appearance of a sea-going floating
island
H. tall trees increase floating
island mobility
Questions 10 -13
Complete the labels on Diagram B below.
Write the correct letter
A
—
H in boxes 10- 13 on your
answer sheet.
Diagram A: Before Pirron
Y
allock Island formation
Diagram B:
After Pirron Y
allock Island
formation
『
12
』
A.
B.
C.
D.
E.
F.
G.
H.
5 meters
30 meters
basalt
200 meters
250 meters
causeway
highway
drainage channel
科技篇
2
You should spend about 20
minutes on Questions 1-14 which are based on the
following Reading Passage.
Questions
1-7
Reading Passage 1 has seven
paragraphs A
—
G
From the list of headings below, choose
the most suitable heading for each paragraph.
Write the appropriate numbers i-x in
boxes 1 -7 on your answer sheet.
List
of Headings
i. Award-winning
wine
ii. Temperature vital to
production
iii. Early caution and
challenge
iv. A delicious taste
v. Picking the grapes, the only easy
step
vi. From grape to wine
vii. The juice flows quickly
viii. Disease brings benefits
ix. The role of climate in taste
x. Obstacles to production
1. Paragraph A
2. Paragraph B
3. Paragraph C
4.
Paragraph D
5. Paragraph E
6. Paragraph F
7.
Paragraph G
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