首页
登录
职称英语
What is the main topic of the passage? [originaltext] What makes it rain?
What is the main topic of the passage? [originaltext] What makes it rain?
游客
2024-10-24
46
管理
问题
What is the main topic of the passage?
What makes it rain? Rain falls from clouds for the same reason anything falls to Earth. The Earth’s gravity pulls it. But every cloud is made of water droplets or ice crystals. Why doesn’t rain or snow fall constantly from all clouds? The droplets or ice crystals in clouds are exceedingly small. The effect of gravity on them is minute. Air currents move and lift droplets so that the net downward displacement is zero, even though the droplets are in constant motion.
Droplets and ice crystals behave somewhat like dust in the air made visible in a shaft of sunlight. To the casual ob-server, dust seems to act in a totally random fashion, moving about chaotically without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The cloud droplet of average size is only 1/2500 inch in diameter. It is so small that it would take sixteen hours to fall a mile in perfectly still air, and it does not fall out of moving air at all. Only when the droplet grows to a diameter of 1/125 inch or larger can it fall from the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size large enough to fall out is the cause of rain and other forms of precipitation. This important growth process is called "coalescence"
选项
A、The mechanics of rain.
B、The climate of North America.
C、How gravity affects air current.
D、Types of clouds.
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3815057.html
相关试题推荐
Nancybecameataxidriverbecause[br][originaltext]I:Hello,Nancy.Iknowy
Nancybecameataxidriverbecause[originaltext]I:Hello,Nancy.Iknowyouare
Whatistheconversationmainlyabout?[br][originaltext]M:Whyareyoulookin
Untilwhattimewillthetornadowatchbeineffect?[br][originaltext]We
Untilwhattimewillthetornadowatchbeineffect?[originaltext]Weinter
Thesepeoplewerearrestedfor_______.[br][originaltext]TheIranianaut
Thesepeoplewerearrestedfor_______.[originaltext]TheIranianauthoriti
Whatisthemaintopicofthepassage?[originaltext]Whatmakesitrain?
Whatisthestudent’sproblem?[br][originaltext]M:Thisbookisduetoday,bu
Whatisthestudent’sproblem?[originaltext]M:Thisbookisduetoday,butIam
随机试题
Ayoungmangoingtojointhearmy(军队)andhadto【C1】______amedicalexaminat
ThemajorsectorsoftheUSeconomyaremuchinfluencedby______.[br][origina
[originaltext]M:Yael,what’sthatinyourhand?W:Comeon,Don.Haven’tyous
Inarecentarticle,mathematicianAczelarguesconvincinglythatthenumber
《规划》提出要实现金融科技应用先进可控、金融科技支撑不断完善、金融科技产业繁荣发
神经症的共同特征为A.起病常与心理社会因素有关 B.主要表现为脑功能失调症状、
2018年7月21日至29日,国家主席习近平出席金砖国家领导人第十次会晤,并访问
反映商业银行对贷款损失的弥补能力和对贷款风险的防范能力的关键风险指标是()。A
H型组织的典型特征是过度分权,各子公司保持了较大的独立性,总部缺乏有效的监控约
(2018年真题)下列各项中,适用于单件、小批生产企业的产品成本计算方法是()
最新回复
(
0
)