轻松学英语每日一练(308)
阅读下面短文，在空白处填入1个适当单词或括号内单词的正确形式。
Deserts
A desert is a beautiful land of __1__ (silent) and space. The sun shines, the wind blows, and time and space seem __2__ (end). Nothing is soft. The sand and rocks are hard, many of the plants even have hard needles instead __3__ leaves.
The size and location of the world's deserts are always __4__ (change). Over millions of years, as climates alter and mountains rise, new dry and wet areas emerge. __5__ within the last hundred years, deserts have been increasing at a __6__ (frighten) speed. This is partly because of natural changes, but those most responsible for creating deserts are men.
In the __7__ (nineteen) century some people living in the English colonies in Australia introduced rabbits into that continent from England. Today there are millions of rabbits __8__ eat every plant in sight. The great desert that lies in the center of Australia is growing, partly due to the rabbit.
Agriculture was first begun in the Tigris-Euphrates Valley (幼发拉底河谷), but today the land there is a desert. In dry areas, people plant crops on land that is poor and arid. When there are one __9__ two years of drought, vegetation dies, the wind blows the top soil away __10__ the land becomes a desert. Goats, sheep and camels eat every plant they can find.
