19
CHANGING ENVIRONMENT
2.2
GRAMMAR
PRESENT PERFECT SIMPLE AND CONTINUOUS
7
a
Read these sentences that describe a similar situation
and answer the questions.
a
I’ve been working for the US Geological Survey for
the last three months on a temporary contract.
b
I’ve worked for the US Geological Survey for three
months now and this is my last day in the office.
1
Which sentence uses the present perfect simple?
Which uses the present perfect continuous?
2
Do both sentences refer to the same period of time?
3
Do both sentences refer to a time starting three
months ago and lasting up to now?
4
Which sentence emphasises a completed action?
5
Which sentence sees the action as temporary and
incomplete at the moment that it is talked about?
7
b
Underline examples of the present perfect simple
and the present perfect continuous in the article. Why
has the writer used these forms in each case?
¬
Language reference and extra practice, pages 126–149
8
Complete the sentences with the present perfect
simple or present perfect continuous form of the verbs
in brackets. Sometimes both forms are correct.
1
In Iceland, the ice
(disappear) at an alarming rate.
2
The Dead Sea
(shrink) at the rate of one
metre per year.
3
Rising sea levels mean that some reclaimed land in
low-lying areas
(already/vanish).
4
I
(work) on the environmental project all year.
5
The Environment Agency
(send) over 115,000
warnings to people at risk of flooding.
6
The environmental lobby
(try) to get the
government to reduce CO
2
emissions for ages.
7
Some scientists
(question) the impact of
climate change.
8
The IPCC
(just/publish) their latest report.
SPEAKING
9
Work in groups. Talk about your environment using
the present perfect simple and continuous. Discuss
some of these topics.
•
the weather
• the seasons
•
wildlife
• endangered species
•
sea levels
Our class has been paying a lot of attention to local
environmental news over the past couple of years, and
we now know that honey bees have been disappearing
at an alarming rate. A top scientist has warned that these
bees could be wiped out in a few years.
Coral bleaching
When sea temperatures rise, corals lose the algae that
feed on them. This causes the coral to turn white and
makes it weaker. In 2005, the US lost half of its Caribbean
coral due to bleaching.
2
Overpopulation has already seen many trees cut down
for fuel, housing and to make way for agriculture. Another
threat comes from tree-killing insects that thrive in the
warmer weather. The forests of the Rocky Mountains in
both the US and Canada have been badly affected since
2000.
Rising sea levels
As glaciers and ice caps melt, the level of the Earth’s
oceans rises.
3
NASA satellites clearly show that the polar ice caps are
melting. NASA calculates that they are shrinking by 9%
a year. The US Centre for Atmospheric Research predicts
that the Arctic could be ice free by 2040.
4
A UN climate change report estimates that the oceans
could rise by up to 58cm by 2100, putting low lying areas
such as the Maldives at risk.
5
A survey of Iceland’s glaciers shows that, since 1995, the
country has lost about 9.5 billion tons of ice each year.
The same thing is happening to glaciers all over the globe.
Threats to humans around the world
The last decade was the hottest ever recorded
according to the World Meteorological Organisation and
future decades will almost certainly see even higher
temperatures.
6
A recent IPCC report says that, since the 1950’s, there
have been changes in many types of extreme events.
Heavier rain has brought death and destruction to many
areas from the United States to Europe and the Far East.
7
While some areas have seen record levels of rainfall,
others have suffered from a lack of rain. Severe droughts
can cause crop failure and famine.
8
A report by the World Health Organisation concludes that
changes in infectious disease transmission patterns are
a likely consequence of climate change. Malaria carrying
mosquitoes are now being found in areas previously too
cold for them to survive in.
