The document discusses energy sources from plants. It provides examples of how scientists are investigating fast-growing plants like water hyacinth that can be used to produce renewable fuel. The energy from green plants is the most important of all energy sources from plants because it is renewable and costs nothing to produce.

3. What kind of energy source
do you see in this song?

11. Positive Compar Superlati
ative ve
cold colder coldest
hot hotter hottest
big bigger biggest
warm warmer warmest
large larger largest
expensiv more the most
e expensive expensive

12. Here are some irregular adjectives.
Positiv Compa Superla
e rative tive
good better best
bad worse worst
little less lest
many more most

13. Comparative form
(a) Short adjectives
With short adjectives, we make
comparative form
by adding –er to the stem.
comparative
comparative
The cheaper plates
The cheaper plates
are over there
are over there

14. (b) Long adjectives
With long adjectives, we put
more before the adjective.
It’scomparativeexpensive to
more expensive to
It’scomparative
more
travel on Friday
travel on Friday
comparative
comparative
It’s more dangerous on the
It’s more dangerous on the
southern slope
southern slope

15. Superlative
form
(a)Short adjectives
For the superlative form, we add
–est to the stem.
Rutland was the
Rutland was the
smallest county in
smallest county in
Britain.
Britain.
Superlative

16. (b)Long adjectives
With long adjectives we put
most before the adjective.
Superlative
Superlative
Who is the most beautiful
Who is the most beautiful
girl in the world?
girl in the world?
Rory Underwood is England’s
Rory Underwood is England’s
most successful rugby player
most successful rugby player
Superlative

17. Listening
Listening Reading
Reading
Speaking
Speaking Writing
Writing

18. Activity 1
Listen “The energy
from plants” and
circle T (true) or F
(false). For the
sentences you
marked false, give
the correct
information.

20. The scientists have never
The scientists have never
begun to investigate fuel
begun to investigate fuel
producing plants.
producing plants.
The energy from plants is
The energy from plants is
renewable.
renewable.
The energy which green
The energy which green
plants supply is useless.
plants supply is useless.

21. Scientists have always
Scientists have always
been interested in plants
been interested in plants
which produce food like
which produce food like
grain or fruit.
grain or fruit.
Water hyacinth is fast-
Water hyacinth is fast-
growing weed which
growing weed which
grows in brackish water.
grows in brackish water.

22. 1
1
2
2

23. 1
1
2
2

24. Activity 2
Read the text and
answer the
questions. What
does the reference
word refer to?

26. 1.It’s not difficult to
1.It’s not difficult to
see…..(line 2)
see…..(line 2)
Green plants
Green plants

27. 2. It is renewable.
2. It is renewable.
(line 5)
(line 5)
Green plants
Green plants

28. 3. They are looking
3. They are looking
at quick-growing…..
at quick-growing…..
(line 18)
(line 18)
Scientists
Scientists

29. 4. It costs nothing to
4. It costs nothing to
produce. (line 4)
produce. (line 4)
Green plants
Green plants

30. 5. But, most
5. But, most
important of all.(line
important of all.(line
4)
4)
Plants
Plants

31. Activity 3
Think of energy
source from plants
that you know and
present in front of
the class.

32. Example Corn is raw
material to produce
ethanol. It’s not
expensive. Moreover, we
use corn cob to produce
electricity energy.

34. Activity 4
Complete each
sentence with
a comparison.

35. 1. Scientists have helped
1. Scientists have helped
framers to produce _______
framers larger
larger
larger
to produce _______
larger
and ________ crops from
and ________ crops from
these plants. (large)
these plants. (large)

36. 2. Breeding new plants
2. Breeding new plants
whish produce ______heavier
crops
whish produce ______heavier
crops
and which resist disease
and which resist disease
better
better
______ .. (heavy, good)
______ (heavy, good)

37. 3. Giant kept is one of the
3. Giant kept is one of the
fastest
world’s
world’s
fastest
______ -growing plants. (fast)
______ -growing plants. (fast)

38. 4. It was never a pleasant
4. It was never a pleasant
beach, but the oil
beach, but the oil
dirtier
dirtier
made it _______. (dirty)
made it _______. (dirty)

39. 5. Today we use ______
5. Today more use ______
we
more
electric energy than
electric energy than
energy from plants. (many)
energy from plants. (many)

40. 6. Energy from coal is the
6. Energy from coal is the
most expensive
most expensive
____________(expensive)
____________(expensive)

41. 7. Water hyacinth is a ______
7. Water hyacinth is a ______
growing in
growing in
faster
faster
fresh water than sugar
fresh water than sugar
cane. (fast)
cane. (fast)

42. 8. The energy from green
8. The energy from green
plant the __________important
plant the __________
most important
most
of all energy from plant.
of all energy from plant.
(important)
(important)