下面文章中有五处需要添加小标题。请从以下选项(A、B、C、D、E和F中选出符合各段意思的小标题。选项中有一项是多余选项。
| A. There is still life in the desert B. There are many deserts in the world C. Some of deserts are very cold D. Almost all of the deserts are low and flat E. Little rain falls in the desert F. Not all deserts are flat and sandy |
You probably know some basic facts about deserts (沙漠). For example, most people know that deserts are dry places where more water evaporates (蒸发) each year than falls even with heavy rain. However, there are many facts about deserts that you may not know. Reading the following may help you find out more about these unusual areas.
Most deserts have less than 10 inches of rain each year. However, in some deserts of South American, it is true that rain almost never falls. In one desert in Chile, no rain has fallen for 45 years in a row! All the rain falls within a single month!
Temperatures in deserts can reach above 37.8℃ during the day, but can fall below zero at night. Areas that are too cold for anything to grow are called "frigid deserts." Other deserts are cold for long periods. The Gobi in Asia has icy temperatures for as long as six months at a time.
Although deserts can be low and flat, some have rocky hills and even mountains. Some also have lakes and plains covered with small rocks. Sand makes up only about 2 percent of North American deserts, 10 percent of the Sahara in northern Africa, and 30 percent of the Arabian Desert.
To survive in a dry desert environment, plants and animals, including humans, must make some adaptation. Desert plants cannot grow too close together because each plant would not get enough water. Other animals stay in holes underground or rest in the shade during the heat of the day.
Deserts cover about one fifth of Earth's land area. The largest desert in the world is the Sahara. The Sahara stretches from the Atlantic Ocean eastward to the Red Sea, spreading across parts of Morocco, Algeria, Tunisia, Libya, Sudan, Chad, Niger, Mali, and Mauritania. It covers an area about the size of the United States.