首页
登录
职称英语
Only special plants can survive the terrible climate of a desert, for these a
Only special plants can survive the terrible climate of a desert, for these a
游客
2024-03-02
44
管理
问题
Only special plants can survive the terrible climate of a desert, for these are regions where the annual range of the soil temperature can be over 75℃. Furthermore, during the summer there are few clouds in the sky to protect plants from the sun’s ray. Another problem is the fact that there are frequently strong winds which drive small sharp particles of sand into the plants, tearing and damaging them. The most difficult problem for all forms of plant life, however, is the fact that the entire annual rainfall occurs during a few days or weeks in spring.
Grasses and flowers in desert survive from one year to the next by existing through the long, hot, dry season in the form of seeds. These seeds remain inactive unless the right mount of rain falls, If no rain falls, or if insufficient rain falls, they wait until the next year. or even still the next. Another factor that helps these plants to survive is the fact that their life cycles are short. By the time that the water from the spring rains disappears--just a few weeks after it fall--such plants no longer need ally.
The perennials(多年生植物) have special features which enable them to survive as plants for several years. Thus, nearly all desert perennials have extensive root systems below ground and a small shoot system above ground. The large root network enables the plant to absorb as much water as possible in a short time. The small shoot system, on the other hand, considerably limits water loss by evaporation(蒸发).
Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long, dry season, just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season. Then, in the next rainy season, they come fully alive once more, and grow new branches, leaves and flowers, just as the grasses and flowers in desert do. [br] The last paragraph is mainly about ______.
选项
A、the comparison between plants in different areas
B、the growth of new leaves in the rainy season
C、water loss by evaporation in the dry season
D、the changes in the leaves of the perennials
答案
D
解析
主旨题。第四段第一句通过another feature引出本段主题句,本句中心词为 perennials和leaves,据此推断答案为D。
转载请注明原文地址:http://tihaiku.com/zcyy/3498233.html
相关试题推荐
[originaltext]W:Nowpeoplearesufferingmorestress,especiallywomen.Iwond
[originaltext]W:Nowpeoplearesufferingmorestress,especiallywomen.Iwond
[originaltext]W:Oh,Jackie,I’vehadsuchaterribleday.M:Youlookexhauste
[originaltext]W:Oh,Jackie,I’vehadsuchaterribleday.M:Youlookexhauste
[originaltext]TheclimateofthewestcoastisthemostmoderateinCanada.
[originaltext]TheclimateofthewestcoastisthemostmoderateinCanada.
Mostworthwhilecareersrequiresomekindofspecializedtraining.Ideally,
【B1】[br]【B20】A、especiallyB、speciallyC、particularlyD、uncommonlyA
【B1】[br]【B12】A、principallyB、unusuallyC、speciallyD、especiallyDprincipally“
[originaltext]M:DidyouseethatTVspecialonNormanRockwelllastnight?W:
随机试题
Moreandmore,theoperationsof’ourbusinesses,governments,andfinancial
计算体重指数时,需要以下哪些数据《》()《》()A.性别 B.年龄 C.身高
下述哪项不符合急性心包炎的临床表现A.心动图示ST段普遍抬高 B.脉压减小
下列关于财务分析内容的说法,错误的是()。A.分析客户盈利能力时,应着重对盈
医疗用毒性药品处方保存期限的时间限定是( )。A.1年 B.2年 C.3年
反胃证的治疗原则应是A.健脾和胃,理气降逆 B.温中健脾,降气和胃 C.温中
下列关于可行域的描述中,正确的是()。 A.可行域可能是平面上的一条线B.
下列情形中,属于投标人相互串通投标的是()。A.两个以上投标人的投标文件具有特
小儿腹概述
最新回复
(
0
)