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
67
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
Ifyouwerestartingatopuniversitytoday,whatwoulditlooklike?Youwouldstartbygatheringverybestmindsfrom【M1】____
TheInternetprovidesanamazingforumforthefreeexchangeofideas.Giventherelativelyafewrestrictionsgoverningaccess
Besidesconcernsabouthowadsaffectindividuals,criticshaveraisedethicalissuesabouthowadvertisingaffectssociety.F
Inanefforttoexplainhowmostoflanguage,whichisnotsodirectlyrelatabletomeaning,derivedfromanonomatopoeicbegi
Doctorsbaffledbyanunexplainedrashonpeople’searsorcheeksshouldbeonalertforaskinallergycausedtoomuch【M1】_____
Languageisfantasticallycomplex.Itsbuilt-inmeansofcombiningandrecombining(nesting)ofitsvariouslevelshave【M1】______
Arabiclanguageisoneoftheworld’smostwidelyusedlanguages.ItistheofficerlanguageofmanyArabnationsinthe【M1】____
Ifourbrainswerecomputers,we’dsimplyaddachiptoupgradeourmemory.Thehumanbrain,therefore,ismore【M1】______comple
Itmaybenosurprisethatthebest-sellingcomputerbooksofarthisyearisPhone:TheMissingManual,bymycolleagueDavidP
Ifourbrainswerecomputers,we’dsimplyaddachiptoupgradeourmemory.Thehumanbrain,therefore,ismore【M1】______comple
随机试题
下列关于函证程序的说法中,正确的是()。
下列句子中,计量单位用法正确的是()。
监理工程师在评审索赔费用时应当遵循的原则不包括( )。
根据《国务院关于投资体制改革的决定》的规定,对于采用投资补助、转贷和贷款贴息方式的政府投资项目,只审批()。
wegiveyouontheattachedsheetfulldetailsregardingpackingandmarking,whichmustbestrictly_____.
钱某工作已满15年,2015年7月1日调到乙公司工作,提出补休年休假的申请,则钱某可以享受的年休假是()天。
甲地重点发展工业,乙地是一座旅游城市,甲地居民的患病比例也要高于乙地,但甲地的树木反而要比乙地长得茂盛。以下各项如果为真,哪项最无助于解释上述现象?()
党对公安机关的政治领导的实现途径包括()。
2008年金融危机爆发后,国际力量对比发生新的此消彼长,世界多极化趋势更加明朗。其主要表现在
ScienceWithoutBordersScienceandtechnologyisamongthefactorsthathavetakenthehumancivilizationtotheleveliten
最新回复
(
0
)