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
Here in the United States, before agricultural activities destroyed the natural balance, there were great migrations of Rocky
Here in the United States, before agricultural activities destroyed the natural balance, there were great migrations of Rocky
admin
2017-06-15
64
问题
Here in the United States, before agricultural activities
destroyed the natural balance, there were great migrations of Rocky
Mountain locusts(蝗虫). Great migrating hordes of these insects
once darken the skies on the plains east of the Rockies where crops【S1】______
were often destroyed; the worst years were those between 1874 to【S2】______
1877. One of these migrating swarms was estimated to contain 1. 24
billion locusts. During the another migration in Nebraska it was【S3】______
estimated that the swarm of locusts averaged half a mile high and
was 100 miles wide and 300 miles long. Usually, these swarms take
up from the ground against the wind, but, once airborne, they turn【S4】______
and fly with it. Warm convection currents(对流)help to lift them,
often at great heights. During the great locust plagues the situation【S5】______
in Nebraska became so serious that the original state constitution
had to be rewritten to take care the economic problems. The new【S6】______
document was known as "The Grasshopper Constitution". It is now
believed that these locusts were a migratory form or phase of the
lesser migratory locust, that is still common there. In this respect,【S7】______
the North American migratory locusts resemble their African
relatives. In both regions the migratory forms rise as a result of【S8】______
crowding and climatic factors. Migratory forms are apparently
natural adaptations which bring about dispersal when locust
populations become too crowded. Unfortunately for our farmers, the【S9】______
migratory form no longer seems to occur regularly, although there
was a serious outbreak as late as 1938 in midwestern United States
and Canada. Actually, there is no reason why the destructive
migratoiy form might not again appear if circumstances become【S10】______
favorable.
【S1】
选项
答案
darken—darkened
解析
时态错误。这里说“蝗虫群曾经遮天蔽日”,有很明显的时态标志词once表示过去,因此应使用一般过去时。
转载请注明原文地址:https://kaotiyun.com/show/QUsK777K
0
专业英语八级
相关试题推荐
Ihaveadreamthatonedaythisnationwillriseupandliveoutthetruemeaningofitscreed,"weholdthesetruthstobese
Thisisaperiodinwhichtheoldworldisslowlybutirreversiblychangingandthecontoursofanewonearejustbeginningto
Educationalphilosophyhaschangedagreatdealinthe50yearssinceIwasinschool.Backthen,forexample,Ihadthehighe
Themostconsistentlyidentifiedteachereffectivenessvariableistimeontask.Thatis,themoretimethatstudentsspendon
Oururgetoclassifydifferentlifeformsandgiveusnamesseemstobeasoldasthehumanrace.
Stoppingcigarettesmokinghasbecomeabigproblemforallgovernments.Indemocraticcountries,theeconomicstrengthofthe
Christmasisthetimetomakethebelovedonesfeelspecial.Ahugandakisswouldprobablybemorethanenoughbutgiftsare
ApprenticeshipshavelongbeenpopularinEurope,butworkforce-orientedhighschooltrainingisnearlyascommonin【M1】______U
Researchonlanguagelearningstrategiesstartedinthe1970s.Forthemostpart,theprogressincognitivepsychologyhadagre
(1)ThatisalessonScottSpector,15,learnedthehardway,whenhisphonestartedblastinghis"AmericanIdolTheme"ringtone
随机试题
试述急性喉、气管、支气管炎的临床特点。
动作电位传播的形式是
与活动有关的疼痛和血尿首先应考虑
胞宫主月经和孕育胎儿的生理功能,必须在
城市污水系统主要包括()。
下列会计科目中,属于损益类的有()。(2.1)
年度终了,日记账、总账和所有明细账必须更换新账,不能延续使用旧账。()
漫步林间,常________草长莺飞、枝叶枯荣,但未必能细________花鸟之名、树木之性;轻________鼠标,可知生物的纲目属种、迁徙演化,却无法________到花果清香,丛林气息。填入划横线部分最恰当的一项是:
Theincreaseinthemarginrate(保证金率)from50%to70%wasnotanattempttostemanyrampant(猛烈的)speculationonthepartoft
BritishCuisine:TheBestofOldandNewBritishcuisine(烹饪)hascomeofageinrecentyearsaschefs(厨师)combinethebest
最新回复
(
0
)