السلام عليكم
هذي حلول الوحدة الرابعة[B]ص75
Exercise A
Set for pairwork. Feed back orally.
Answers
1- It’s a graph.
2- Average monthly rainfall in Abu Dhabi and the Sahara.
3- The same information as Figure A.
4- No – you need to take measurements outside.
5- Measure rainfall.
6- The main fact is probably that it is wetter in
Exercise B
Make sure students realize that the graph and the table
give the same information. Show that you can therefore
complete one with information from the other.
Set for individual work then pairwork checking.
Feed back onto the board or onto an OHT.
Exercise C
Exploit the visual. Give students plenty of time to read the
sentences and guess or work out the missing information.
Play the recording. Feed back orally.
Tape$$$$$$ and Answers
1 Deserts cover one-third of the Earth’s surface.
2 13per cent of the world’s population live in deserts.
3 No rain fell for over 40 years in the Atacama desert in
Chile.
4 Wind has sometimes carried sand from the Sahara to
the UK.
5 The Sahara occupies around eight percent of the
world’s land area.
6 There are about 1,200 different types of plants –
flowers and trees – in the Sahara.
7 The Sahara is expanding southwards at an average of
nearly one kilometre a month
ص76
Exercise A
Answers
1 Answers depend on students.
2 It’s about the Sahara.
1 De$$$$$$ion
2 History
3 Explanation
Exercise B
Answers
1- 9 million km2
2- 1,600 kilometres
3- 5,000 kilometres
4- Algeria, Libya, Egypt, the Sudan, as well as some of
Mauritania, Mali, Niger and Chad
5- a. Arabic – sahra; b. Sanskrit – sagara
6- desert
7- big sea or ocean
8- giraffes, cows, deer, fish
9- signs of a lake and rivers
Exercise D
Answers
Key points are that the Sahara was once an agricultural
area with lakes and rivers. A change in the Earth produced
a change in the climate. Perhaps the movement of the
people into the Nile valley is also a key point
ص77
Exercise A
1 scientist
2 evidence
3 ancient
4 farmers
5 discovery
6 thousand
7 million
8 millilitres
9 millimetres
Exercise B
Answers
1 Introduction: the structure of the talk
2 Facts about present-day Sahara
3 Origins of the name
4 Evidence of ancient life – animals
5 Evidence of ancient life – lakes and rivers
6 Evidence of ancient life – agriculture
7 Reasons for the change
8 How climate change happens
9 Results of the change
10 Preview of next talk
ص78
Exercise A
Answers
a The Sahara is the largest desert in the world.
b It occupies most of the northern third of the continent
of Africa.
c It covers nine million square kilometres.
d It comprises most of the land area of the Arab
countries of Algeria, Libya, Egypt and the Sudan.
e Some people believe that the name comes from the
Arabic word for desert.
Exercise B
Answer
Making the Sahara green again.
Exercise C
Answers
1 2,000 m
2 Libya
3 1984
4 3,000 km
5 5 million m3
6 1,500 km2
7 May 2003
8 the Red Sea
9 39
10 4 km2
11 25 km2
12 several degrees lower
Exercise D
Answers
1 Introduction: the structure of the talk
2 Present projects in the Sahara – wells and oases
3 Present projects in the Sahara – the Great Man-Made
River
4 Present projects in other countries – Saudi Arabia
5 Present projects in other countries – the UAE
6 Conclusion
ص79
Exercise A
Answers
Findings
The ice cube melts, i.e., changes/converts to water.
You may observe some condensation on the inside of the
glass. This shows that some of the water changes to gas
and then back to water on the side of the glass.
Conclusion
The ice changes to water because it gets hotter. Some of
the water changes to gas and then back to water on the
side of the glass.
Exercise B
Tape$$$$$$ and Answers
Three natural cycles keep the plants and animals on Earth
alive. The cycles are the carbon and oxygen cycle; the
nitrogen cycle; and the water cycle. All living things need
oxygen (O), carbon (C), nitrogen (N) and water, which is, of
course, a combination of hydrogen and oxygen (H2O).
How does a natural cycle work? The process is simple.
Something converts or changes the form of a substance.
Something else converts it back again. For example, in the
water cycle, the heat of the Sun converts liquid water in
rivers and seas into a gas. We see this gas in the sky as a
white, grey or black cloud. Then, the gas cools and changes
back to a liquid – called rain – or a solid – called snow.
Exercise C
Answers
1, 2
Table 1: Natural states of water
Examples in $$$$ Other possible examples
Liquid water, rivers, seas ponds, pools, puddles,
streams, oceans, lakes
Solid snow ice, hail
Gas clouds steam, spray, vapour
3 When you heat it or cool it. (Note that students may
not be familiar with the word cool as a verb. Highlight
the point.)
4 Depend on students.
ص 80
(E (A
1- in afternoon at 3.15
2- school cafe
3- she doesn`t say
(E(B
1-
things
actually
caurse do
free
so good
about
sorry make
until
can
sure see
Greet
about
then
(E(D
talk
nature
water
nitroger
oxygen
technical
week
draw
(E(E
water vapour rises into the air
water vapour condenses
[couds move .....the land[/B
colds rise
colds cool
rain falls.....land
water......rivers
