Only a generation ago, Mauritania's capital city was many day's walk from the Sahara. Today it is in the Sahara. 1.__________The sand blows through the city streets and piles up in 2.__________walls and fences. The desert stretches out as far as the
eye can see.
In some parts of the Amazon rain forest in brazil, all the trees have cut down. The earth lies bare and dry in the 3.__________ hot sun. Nothing grow there anymore. 4.__________Over vast areas of every continent, the rainfall and vegetation necessary for life is disappearing. Already 5.__________ more than 40 percent of the earth's land is desert and 6.__________ desert-like. About 628 million people--one out of seven--live in these dry regions. In the past, they have managed to survive, but in difficulty. Now, largely through problems 7.__________ caused by modern life, our existence is threatened by the 8.__________ slow, steady spread of the earth's deserts.
Many countries first became concerned in 1970s after 9.__________ a terrible drought and famine destroyed Africa's Sahel,the fragile desert along the south edge of the Sahara.
Thousands of people died even though there was a worldwide effort to send food and medicine to the starved people.
参考答案
1. day's → days'
2. in → against
3. have ∧ cut → been
4. grow → grows
5. is → are
6. and → or
7. in → with
8. our → their
9. in ∧ 1970s → the
