首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Every geologist is familiar with the erosion cycle. No sooner has an area of land been raised alive sea-level than it becomes s
Every geologist is familiar with the erosion cycle. No sooner has an area of land been raised alive sea-level than it becomes s
admin
2013-11-29
42
问题
Every geologist is familiar with the erosion cycle. No sooner has an area of land been raised alive sea-level than it becomes subject to the erosive forces of nature. The rain beats down on the ground and washed【51】the finer particles, sweeping them into rivulets and then into rivers and out to sea. The frost freezes the rain water in cracks of the rocks and breaks【52】even the hardest of the constituents of the earth’s crust. Blocks of rock dislodged at high levels are brought down by the force of gravity. Alternate heating and【53】of bare rock surfaces causes their disintegration. In the dry regions of the world the wind is a powerful force in removing material from one area to another. All this is natural. But nature has also provided certain defensive forces. Bare rock surfaces are in【54】course protected by soil itself dependent initially on the weathering of the rocks. Slowly【55】surely, different types of soil with differing "profiles" evolve the main types depending primarily on the climate. The protective soil covering, once it is formed, is held together by the growth of vegetation. Grass and herbaceous plants,【56】long, branching tenuous roots, hold firmly together the surface particles. The【57】is true with the forest cover. The heaviest tropical down- pours beating on the leave of the giant trees reach the ground only【58】spray, gently watering the surface layers and penetrating along the long passages provided by the roots to the lower levels of the soil. The soil, thus protected by grass, herb, or trees, furnishes a quiet habitat for a myriad varied organisms-earth-worms that importantly modify the soil, bacteria, active in their work of converting【59】leaves and decaying vegetation into humus and food for the growing plants. Chemical action is constantly taking【60】. Soil acids attack mineral particles and salts in solution move from one layer in the soil to another.
选项
答案
place
解析
意思为“化学作用持续地进行”。
转载请注明原文地址:https://kaotiyun.com/show/XmhO777K
0
考博英语
相关试题推荐
Oldpeoplearealwayssayingthattheyoungpeoplearenot【51】theywere.Thesamecommentis【52】fromgenerationtogenerationan
Oldpeoplearealwayssayingthattheyoungpeoplearenot【51】theywere.Thesamecommentis【52】fromgenerationtogenerationan
Aboutadecadeago,then-RepublicanHouseleaderNewtGingrichraisedabigstirwhenheimpliedthatamother’sdrowningofher
Aboutadecadeago,then-RepublicanHouseleaderNewtGingrichraisedabigstirwhenheimpliedthatamother’sdrowningofher
MenhaveoftenbeenpraisedbybeingtoldthattheywereassmartasaPhiladelphialawyer.Nooneknowswhythereissomething
Theevolutionofsexratioshasproduced,inmostplantsandanimalswithseparatesexes,approximatelyequalnumbersofmalesa
Stratford-on-Avon,asweallknow,hasonlyoneindustry—WilliamShakespeare—buttherearetwodistinctlyseparateandincre
Stratford-on-Avon,asweallknow,hasonlyoneindustry—WilliamShakespeare—buttherearetwodistinctlyseparateandincre
Stratford-on-Avon,asweallknow,hasonlyoneindustry—WilliamShakespeare—buttherearetwodistinctlyseparateandincre
随机试题
微分方程y’’一2y’=x的特解应设为()
患者,男,48岁,胸骨后疼痛3h,体检BP12/8kPa(90/60mmHg)双肺有湿啰音,心电图心前导联ST段明显抬高呈弓背向上的单向曲线,偶发室性期前收缩,在送入病房途中突发抽搐,经抢救无效死亡。死亡原因最可能为
利用医学影像对人体正常组织或病变大小、位置、范围、毗邻关系的判断是基于图像分析得出的,而图像显示效果又是由窗口技术来调节的。以观察正常组织或病变组织为目的的图像密度、对比度调节技术称为窗口技术,包括窗宽和窗位。若窗宽变为100Hu,窗位变为100Hu,
各年龄阶段之乳牙龋病发生的部位特征是
主清肺与胃之火的药物是()主清心与小肠之火的药物是()
静脉注射某药,X0=60mg,若初始血药浓度为15μg/ml,其表观分布容积是()。
A.烟酸类B.贝丁酸类C.胆酸螯合剂D.胆固醇吸收抑制剂E.HMG-CoA还原酶抑制剂阿昔莫司属于()
A、热服B、冷服C、空腹服D、饭后服E、饭前服滋补药宜()
设备监理的依据主要有()。
奠定了班级授课制理论基础的《大教学论》的作者是()。
最新回复
(
0
)