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
2018-05-25
61
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/OloK777K
0
专业英语八级
相关试题推荐
Today,Iamgoingtoidentifysometypicalresearchproblemsandalsosharewithyouthesolutionstotheseproblems.Thefirst
A、Problemsabouttheirwork.B、Problemsaboutinterpersonalrelationship.C、Problemsabouttheirchildren.D、Problemsaboutabi
A、Writingavacationmemo.B、Writingtotheformerrenters.C、Makingacontractbeforesendingmoney.D、Usingcreditcardtomak
A、Hehassomementalproblems.B、Heistoooldtoknowwhatheisdoing.C、HewantstohaveagoodChristmas.D、Hehasgotinto
A、Thelessdiscussionthebetter.B、Themorediscussionthebetter.C、Youmayconsultparents.D、Youmayconsultanadvisor.D本题
SuggestionsofReadingActivitiesI.Three【T1】______phasesofreading【T1】______—beforereading—inthecourseofreading—a
SuggestionsofReadingActivitiesI.Three【T1】______phasesofreading【T1】______—beforereading—inthecourseofreading—a
SuggestionsofReadingActivitiesI.Three【T1】______phasesofreading【T1】______—beforereading—inthecourseofreading—a
SuggestionsofReadingActivitiesI.Three【T1】______phasesofreading【T1】______—beforereading—inthecourseofreading—a
随机试题
目前认为,可以肯定改善COPD患者长期预后的治疗措施是
有关周围神经药物注射伤的机制。以下哪项不正确
A.利巴韦林B.阿昔洛韦C.更昔洛韦D.奥司他韦E.阿糖腺苷疱疹病毒感染首选
下列选项中,不是牙周基础治疗的内容是
局部切取活组织检查,下列叙述错误的是
下列哪些情况下,法院应裁定诉讼中止?
资本主义农产品的社会生产价格取决于()。
由于银行的业务性质要求银行要维持存款人、贷款人和整个市场的信心,因此,银行通常将()看作对其市场价值最大的威胁。
智力
Forthispart,youareallowed30minutestowriteashortessayentitledBeaChild’sSlave?Youshouldwriteatleast150word
最新回复
(
0
)