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【单选题】
Newspapers often tell us of floods in some parts of the United States. Nearly every year on the great central drainages heavy rains and melting snow cause the waters to pour out the mountains and plains, to turn brooks into torrents, and to swell quiet streams into wild uncontrolled rivers. From Cairo to New Orleans, and from Pittsburgh to Paducah, the cry 'River rising!' is a familiar yet fearful voice. . . When the rivers sometimes become too high or too swift to be controlled communities are flooded, families flee from their homes, croplands are washed out, and transportation comes to a halt. Hunger, disease, and death follow the wild waters. Although given less publicity, the agricultural damage done by the many smaller, more frequent floods usually far exceeds the losses caused by the very grand ones. In the Central States, ditches and drains cause the flows from spring rains and melting snow to run far more rapidly than in the days before white men settled on the land. Once, excess spring flood waters emptied into lakes and swampy lands, there to be detained for slow release into stream and rivers. Now, systematic drainage has actually eliminated these natural reservoirs. In the more rolling sections of the East, spring runoff was formerly absorbed and held temporarily in the porous soils beneath the unbroken expanse of forest. When large areas were converted to farm use, removal of the forest and the practice of up-and-down hill plowing deprived the soils of much of their ability to catch and store water. The effects of eliminating the natural forest cover are shown in the gullied farm lands and widened stream channels found in some densely settled areas. Partly because the stream channels are more or less filled with material washed down from the uplands, and partly because storm runoff has increased, the channels are today no longer able to carry all the flow from heavy rains. This explains why the streams overtop banks far more often than in the days before settlement. The best title for the selection would be______.
A.
River Rising! River Rising!
B.
Forests and Floods
C.
Flooding in the U. S.
D.
The Results of Flooding
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【单选题】(2019·哈尔滨中考)点(-1,4)在反比例函数y= 的图象上,则下列各点在此函数图象上的是( )
A.
(4,-1)
B.
(- ,1)
C.
(-4,-1)
D.
( ,2)
【单选题】若点P(-2,3)在奇函数 的图象上,则下列各点中,一定在函数 的图象上的点是
A.
(-2,-3)
B.
(2,3)
C.
(2,-3)
D.
(-2,3)
【单选题】某反比例函数的图象经过点A(-3,6),则下列各点中不在此函数图象上的是( )
A.
(3,-6)
B.
(6,3)
C.
(-2,9)
D.
(-9,2)
【单选题】在第一章 “序言” 中,作者引用培根的论述说明了科学是( )
A.
B.
C.
力活动
D.
【判断题】猪传染性萎缩性鼻炎不能影响猪的生长发育。()
A.
正确
B.
错误
【单选题】若反比例函数的图象过点(3,2),那么下列各点中在此函数图象上的点是(  )
A.
(- 2 ,3 2 )
B.
(9, 2 3 )
C.
(- 3 ,2 3 )
D.
(6, 2 3 )
【判断题】猪传染性萎缩性鼻炎是由病毒引起的。()
A.
正确
B.
错误
【单选题】如果反比例函数的图象经过点(3,2),那么下列各点中在此函数图象上的点是 [     ]
A.
(- ,3 )
B.
(9, )
C.
(- ,2 )
D.
(6, )
【单选题】已知点(3,6)在反比例函数y= k x (k≠0)的图象上,那么下列各点中在此函数图象上的点是(  )
A.
(-3,6)
B.
(3,-6)
C.
(2,-9)
D.
(2,9)
【多选题】()能引起猪的繁殖障碍。
A.
猪伪狂犬病
B.
猪传染性萎缩性鼻炎
C.
猪细小病毒病
D.
副猪嗜血杆菌病
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