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. 10.__________


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