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Recordings of angry bees are enough to send big, tough African elephants running away, a new study says. Beehives (蜂窝)-either recorded or real-may even prevent elephants from damaging farmer's crops. In 2002, scientist Lucy King and her team found that elephants avoid certain trees with bees living in them. Today,  Lucy wants to see if African honeybees might discourage elephants from eating crops. But before she asked farmer to go to the trouble of setting up beehives on their farms, she needed to find out if the bees would scare elephants away. Lucy found a wild beehive inside a tree in northern Kenya and set up a recorder. Then she threw a stone into the beehive, which burst into life. Lucy and her assistant hid in their car until the angry bees had calmed down. Next,Lucy searched out elephant families in Samburu National Reserve in northern Kenya and put a speaker in a close to each family. From a distance, Lucy switched on the pre-recorded sound of angry bees while at the same time recording the elephants with a video camera. Half the elephant groups left the area within ten seconds. Out of a total of 17 groups, only one group ignored the sound of the angry bees. Lucy reported that all the young elephants immediately ran to their mothers to hide under them. When Lucy Played the sound of a waterfall (瀑布) instead of the angry bees to many of the same elephant families, the animals were undisturbed. Even after four minutes, most of the groups stayed in one place. Lucy is now studying whether the elephants will continue to avoid the sound of angry bees after hearing it several times. She hasn't tested enough groups yet to know, but her initial (最初的) results were promising enough to begin trials with farmers. She has now begun placing speakers in the fields to see if elephants are frightened away. 小题1:We know from the passage that elephants may be frightened of . A.loud noises B.some crops C.video cameras D.angry bees 小题2:As mentioned in the passage, Lucy A.works by herself in Africa B.needs to test more elephant groups C.has stopped elephants eating crops D.has got farmers to set up beehives on their farms 小题3:Why did Lucy throw a stone into a wild beehive? A.To record the sound of bees. B.To make a video of elephants. C.To see if elephants would run away. D.To find out more about the behavior of bees. 小题4:Which of the following is true according to the passage? A.Young elephants ignore African honeybees. B.Waterfalls can make elephants stay in one place. C.Elephants do not go near trees with bees living in them. D.Farmers do not allow Lucy to conduct tests in their fields.
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参考答案:
举一反三
【单选题】预算线绕着它与横轴的交点向外移动的原因是( )
A.
商品X的价格下降了
B.
商品Y的价格下降了
C.
消费者的收入增加了
D.
以上都不是
【单选题】预算线绕着它与横轴的交点向外移动的原因是
A.
商品 X 的价格下降了
B.
商品 Y 的价格下降了
C.
消费者的收入增加了
D.
商品X和Y的价格按同样的比率上升
【单选题】肠鸣音活跃及亢进见于下列疾病,但除外
A.
低血钾
B.
急性肠炎
C.
机械性肠梗阻
D.
服用泻药
E.
胃肠道大出血
【单选题】柴油机上调速器的作用是根据负荷的变化,调节(),使柴油机能够以稳定的转速运转。
A.
供油次数
B.
供油时间
C.
供油压力
D.
供油量
【单选题】预算线绕着它与横轴的交点向外移动的原因是
A.
商品X的价格下降
B.
商品Y的价格下降
C.
消费者的收入增加了
D.
商品X和Y的价格按照同样的比率上升
【单选题】预算线绕着它与横轴的交点向外移动的原因是
A.
商品Y的价格下降了
B.
商品Y的价格上升了
C.
消费者的收入增加了
D.
确定
【单选题】预算线绕着它与横轴的交点向外移动的原因是()
A.
商品 X 的价格下降了
B.
商品 Y 的价格下降了
C.
消费者的收入增加了
D.
以上都不对
【判断题】将油量调节机构(油泵齿条或拉杆)固定在某一位置(每循环供油量不变)时,改变柴油机的外负荷,使柴油机转速变化,这样测得的柴油机的主要性能指标和工作参数随转速n而变化的规律,叫柴油机的速度特性
A.
正确
B.
错误
【简答题】柴油机的速度特性是指在喷油量调节机构的位置被固定时,柴油机的性能指标和有关参数随柴油机转速的变化规律。当喷油量调节机构固定位置为标定喷油量位置时的速度特性又称为()。
【单选题】当柴油机转速保持不变时,其性能参数随负荷而变化的关系,称为柴油机的()。
A.
负荷特性
B.
速度特性
C.
万有特性
D.
转速特性
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