1. Unit: Environment
Topic: How to Preserve Environment
Mathayomsuksa 2

2. What is the world coming to?

3. VDO

4. What did you see in the VDO?
• Flooding in Thailand

6. vocabulary
• destroy

7. vocabulary
• climate

8. vocabulary
• erode

9. vocabulary
• steam

10. vocabulary
• lumber

11. vocabulary
• shelter

12. vocabulary review
climate
shelter

13. vocabulary review
erode
destroy

14. vocabulary review
steam
lumber

15. Structure
“have to”
Use of Have to
• In general, have
to expresses impersonal obligation. The subject
of have to is obliged or forced to act by a
separate, external power (for example, the Law
or school rules). Have to is objective. Look at
these examples:

16. Structure
“have to”
Form of Affirmative Sentence
subject have infinitive with to
In England, most school children have to protect
the forest.
Form of Negative Sentence
do/does/did
subject have infinitive with to
not
In France, you do not have to cut the trees.

17. structure review
“have + infinitive with to”
“have + doesn’t/don’t + have + infinitive with to”
What should we fill in the blank?
Honey and Deep have to plant (plant) the trees.
_____________
have to water
Powly and Joseph ___________________ (water)
the trees everyday.
doesn't have to cut
Jason _____________________(not, cut) the trees.

18. Save the Forest (1)
A change is coming in the forest. Scientists are
trying to make the logging companies stop
clear cutting. We have to protect the
fish, wildlife, and water quality. They have
value, too. The forest is a beautiful place that
people should be able to enjoy.
It changes everything when the all the trees
are cut. The trees, animals, and water depend
on each other. Many plants and animals
disappear. The water level in the ground
changes. It can even affect our climate.

19. Save the Forest (2)
This does not mean some of the trees cannot be
cut. It just means all the trees in one place cannot
be cut at one time. It means that you plant new
trees when the old ones are cut. When trees are
cut in this way, the land does not erode. The
streams do not fill with dirt and the animals are
not destroyed.
The industry is beginning to cut trees this way.
They are leaving many dead trees so small animals
will have homes. They are leaving many trees
alone to give shade and shelter for animals. This
also means that the forest's trees are not all the
same kind. This seems very import to the survival
of the forests.

20. Save the Forest (3)
Both the loggers and the forest scientists
are trying to agree on things. They have to
balance the lumber we need with the
forest's protection. A good rule seems to be
not to cut more than you grow each year.

21. Activity 1
True or False
Direction: Read the statements below and answer True
or False.

22. True or False
1. Scientists are trying to make the
logging companies stop clear
cutting.
True False

23. True or False
2. The forest is a beautiful place that
people should not be able to
enjoy.
True False

24. True or False
3. The trees, animals, and water
depend on each other.
True False

25. True or False
4. You plant new trees when the old
ones are cut.
True False

26. True or False
5. People are not leaving many trees
to give shade and shelter for
animals.
True False

27. True or False
6. The good rule seems to be not to
cut more than you grow each year.
True False

28. Activity 3
First Important Priorities
Part 1
• Discuss in the group about the effects of
destroy the forest and write it down in the
blank.
Part 2
• Discuss in the group about the important
priorities effects of destroy the forest then
write it down in the order and give the reasons
why it is the most/least important.

31. Activity 4
Fantasize
Direction:
Think and discuss in your group about
“If there were not any tree in the
world, what would you do?”