[00:05.49]Friend or Enemy?'Kill it!' cried Debbie. 'Certainly not,' said Simon.
[00:13.74]'Why? You're not frightened of it, are you?It's only an insect.'
[00:19.62]'It isn't an insect,Debbie,though it might look like one.
[00:24.87]Actually, it's a very useful creature.
[00:28.81]The programme I watched last night has completely changed my views on spiders.
[00:34.98]Do you want to hear about it?'
[00:38.24]'Not really,' sighed Debbie'but I suppose you're going to tell me anyway.'
[00:43.89]'Spiders,' said Simon,ignoring her remarks,
[00:48.93]'are the enemies of insects and the friends of humans.
[00:53.89]That's something that Chinese farmers realized years ago
[00:58.93]and scientists are only beginning to understand today.
[01:04.08]'Do you know that in parts of China,in the autumn,
[01:09.25]farmers build shelters for spiders and put them all over their fields?
[01:15.31]They're like little cone-shaped tents made of straw
[01:20.35]and the spiders can survive the winter in them.
[01:24.92]When spring comes, the spiders emerge healthy and hungry,
[01:30.88]at the same time as millions of insects arrive to attack the farmers' crops.'
[01:38.04]So the spiders fill their empty stomachs,
[01:43.37]and the fanners whose fields are protected are happy.
[01:47.81]They've saved their crops and their money.
[01:51.65]Because of the spiders their expenditure on insecticides is nil.'
[01:58.20]'So everyone's happy except the insects,' said Debbie.
[02:03.17]'Right,and now this natural method of pest control
[02:08.44]is being copied all over the world.'
[02:12.21]'Interesting,'said Debbie.'But now I really must go and...' 'Wait,'cried Simon.
[02:20.15]'There's more.Do you know what is stronger than steel,
[02:25.71]lighter than a feather and as elastic as a rubber band?'
[02:30.86]'No. What is it?'
[02:33.91]'It's the silk that spiders make their webs with.
[02:38.28]And scientists are trying to develop a material with similar properties.
[02:43.63]They plan to use it in spacecraft,artificial organs like hearts,
[02:49.80]and to make really bullet-proof vests.'
[02:54.05]'I still think spiders are nasty,' said Debbie.
[02:58.63]'Their bites are poisonous, aren't they? They're dangerous.'
[03:03.59]'To insects, yes, but to people, rarely.
[03:08.03]But even their poison is useful.
[03:11.69]Doctors think it might be used to treat brain disorders in humans.'
[03:16.94]'That's good news for you, then,'laughed Debbie.
[03:21.01]'But seriously,I get your point, Simon.
[03:24.85]We should try to understand things in nature and not destroy them.'
[03:29.71]LISTENING
[03:34.39]Understanding descriptions and identifying pictures
[07:36.07]MORE LANGUAGE INPUT(Ⅵ)
[07:40.02]Reading
[07:44.69]Small creatures?
[07:47.57]People often think that insects are small delicate creatures.
[07:52.61]But in reality, they are tough animals.
[07:56.87]As a group,they are much tougher than many bigger animals that we know well
[08:02.74]such as birds and fish, cats and dogs.
[08:07.39]Insects have six legs and three body parts.
[08:12.96]Their antennae and shells help them to detect and protect.
[08:18.10]Can you imagine that insects,
[08:21.76]with their special body structure and power of senses,
[08:26.23]destroy about 10% of the world's food supplies every year?
[08:31.87]Insects have an ability to breed rapidly.
[08:36.62]This enables them to develop large populations.
[08:41.38]If you put all the insects in the world together,
[08:45.82]they would weigh more than all the people
[08:49.79]and the rest of the animals on the earth!
[08:53.63]Small creatures?
[08:56.37]Yes,but with enormous strength.
[08:59.90]Listening
[09:04.47]Food Web
[09:07.11]All living things,except plants, depend on other living things.
[09:13.27]They eat other species but are also eaten by still others.
[09:18.73]They are part of a food chain or a food web inthe world of nature.
[09:25.50]In this listening exercise,you will be asked to draw a food web.
[09:30.83]Listen to the statements carefully. [09:34.28]Fill the missing names of the living things in the boxes.
[09:38.95]Then draw arrows to show what eats what.
[09:43.92]Remember the arrows in a food web always point from food to feeder.
