新概念四冊口語練習（一）
來源：
小編： 167
Use your own words to paraphrase the following sentences.
1. The only way that they can preserve their history is to recount it as sagas---legends handed down from one generation of storytellers to another.
2. These legends are useful because they can tell us something about migrations of people who lived long ago, but none could write down what they did.
3. But the first people who were like us lived so long ago that even their sagas, if they had any, are forgotten.
4. fortunately, however, ancient men made tools of stone, especially flint, because this is easier to shape than other kinds.
5. Stone does not decay, and so the tools of long ago have remained when even the bones of men who made them have disappeared without trace.
6. Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals.
7. We owe a lot the birds and beasts that eat insects but all of them put together kill only a fraction of the number destroyed by spiders.
8. Spiders are not insects, as many people think, nor even nearly related to them.
9. It is impossible to make more than the wildest guess at how many they kill, but they are hungry creatures, not content with only three meals a day.
10. It has been estimated that the weight of all the insects destroyed by spiders in Britain in one year would be greater than the total weight of all the human beings in the country.
