1Choose the words or expressions and complete the passage (选择最恰当的单词或词语，完成短文)

1．We have always been warned of the dangers of the forest fires. They cause     1    to a forest. They kill many plants and animals in an eco-system, which is a group of living things and their environment. But have you ever heard of a forest fire that can be     2     for a forest?

2．People start some of the fires with special reasons to actually do well to the eco-system.

3．In fact, fires are a natural part of any eco-system. Without fires, the oldest and largest trees would stop sunlight from reaching the forest floor. Fires can       3       some of these old trees. When the trees die, they provide something good for the earth. New trees can grow strong and healthy in their place.

4．Some trees even need fires to grow. These trees hold their seeds(种子) inside. Heats from a fire allow the coat of the seeds to open up. Then the seeds fall to the ground and have the 4 to grow.

5．Scientists, who know about nature’s needs, start some of these fires, called controlled burns. A fire is started and kept under control. This way, the fire does not spread out of the area or 5    a large space of the forest. Fires can be dangerous for animals. Even when animals continue to live after forest fires, they can go hungry   6     their food has been damaged in the fire. Small, controlled fires mean that animals will not have to move far to find food. After some time, small plants begin to grow. Animals return soon after the plants return. This   7  makes an eco-system.

6．So the next time you hear about a forest fire, think about the good as well as the bad. It may take a new eco-system a while to return, but it will likely come back stronger and healthier than ever.

1.A. illness            B. difficulty       C. damage      D. flood

2.A. helpful            B. powerful         C. harmful     D. awful

3.A. take the place of  B. get ready for    C. be bad for  D. get rid of

4.A. time               B. water            C. chance      D. skill

5.A. discover           B. cover            C. but         D. waste

6.A. because            B. although         C. but         D. so

7.A. almost             B. again            C. never       D. even

Choose the words or expressions and complete the passage (选择最恰当的单词或词语，完成短文)
1．We have always been warned of the dangers of the forest fires. They cause     1   to a forest. They kill many plants and animals in an eco-system, which is a group of living things and their environment. But have you ever heard of a forest fire that can be     2    for a forest?
2．People start some of the fires with special reasons to actually do well to the eco-system.
3．In fact, fires are a natural part of any eco-system. Without fires, the oldest and largest trees would stop sunlight from reaching the forest floor. Fires can       3      some of these old trees. When the trees die, they provide something good for the earth. New trees can grow strong and healthy in their place.
4．Some trees even need fires to grow. These trees hold their seeds(种子) inside. Heats from a fire allow the coat of the seeds to open up. Then the seeds fall to the ground and have the 4 to grow.
5．Scientists, who know about nature’s needs, start some of these fires, called controlled burns. A fire is started and kept under control. This way, the fire does not spread out of the area or 5   a large space of the forest. Fires can be dangerous for animals. Even when animals continue to live after forest fires, they can go hungry   6    their food has been damaged in the fire. Small, controlled fires mean that animals will not have to move far to find food. After some time, small plants begin to grow. Animals return soon after the plants return. This   7 makes an eco-system.
6．So the next time you hear about a forest fire, think about the good as well as the bad. It may take a new eco-system a while to return, but it will likely come back stronger and healthier than ever.

What do you do if you're in trouble on a lonely island? Surely you need to find a way to get in touch with the outside world. Your best chance of doing this is to draw the attention of a passing plane.
Body signals (信号)
Pilots from different countries understand body signals if they have the correct training, When you wave your arms up and down in a straight line, it means, "yes". When you point downwards and swing your arm from side to side, it means "no". If you want the pilot to know that it's safe to land, push your hands out in front of you and bend (弯曲) your knees. If you want to say that it's not safe to land, put your arms in the air and move them to one side.
Smoke signals
The smoke from a fire can be seen from far away, so it’s a good way to draw attention. If the weather is dry, it isn’t hard to start a fire. Remember, however, that fires can be very dangerous if they get out of control. Never light a tire unless you're sure that it can’t spread. If the ground is dark, light smoke can be seen more easily. Green grass and leaves produce light smoke.
Ground-to-air signals
It's a good idea lo build some signals, too. Use large pieces of wood to make the symbols (标记). If you can't find any wood, use earth. Some useful symbols are:
F "I need food and water"
II "I need medicine."
I "I am badly hurt."
X "I am unable lo move from here."
Pilots' replies
If the pilot lowers the plane's wings from side to side, this means: "message received and understood" (At night, the pilot flashes the plane's green lights.) If the pilot flies the plane in a clockwise circle, this means "message received hut not understood" (At night, the: pilot flashes the plants red lights.)
However, there is no signal which means "message not received. Why not'?
【小题1】How many signals can we use to draw the attention of the passing plane if you're in trouble?