问题 填空题

几年来,由于人口增长,人类对自然的索取变本加厉,导致生态环境严重恶化,沙尘暴发生的频率增高,据报道2 000年春至今,沙尘暴多次肆虐,波及大半个中国,发生频率和含沙量都是空前的.沙尘暴期间,灰尘弥漫,给人们的生活带来很大影响,给国家经济造成严重损失.右图是科学工作者对我国北方地区草原、森林、荒漠面积变化的调查结果.这对研究我国近几年来华北地区多次出现沙尘暴天气有很大的帮助.

(1)北方“沙尘暴”天气具有______、______、______等特点.

(2)“沙尘暴”天气逐年加剧说明我国北方______受到了严重破坏.

(3)我国北方地区频繁出现“沙尘暴”的主要原因有______

①在草原上过度放牧②采伐森林,开垦耕地③工业的发展④黄河出现断流现象

A、①②B、①③C、②③D、①②③④

(4)请你分析植被和沙尘暴形成的关系.______

(5)请你根据生态平衡的原理提出治理沙尘暴的措施.______.

答案

沙尘暴 是沙暴  和尘暴  两者兼有的总称,是指强风把地面大量沙尘物质吹起并卷入空中,使空气特别混浊,水平能见度小于 一百米的严重风沙天气现象.其中沙暴系指大风把大量沙粒吹入近地层所形成的挟沙风暴;尘暴则是大风把大量尘埃及其它细粒物质卷入高空所形成的风暴.沙暴就是风挟带大量尘沙、干土而使空气混浊、天色昏黄的现象.

(1)1993年:4月至5月上旬,北方多次出现大风天气.4月19日至5月8日,甘肃、宁夏、内蒙古相继遭大风和沙尘暴袭击.其中5月5日至6日,一场特大沙尘暴袭击了新疆东部、甘肃河西、宁夏大部、内蒙古西部地区,造成严重损失.近4年春季,我国境内共发生53次(1999年9次,2000年14次,2001年18次,2002年12次)沙尘天气,2002年春季,我国北方共出现了12次沙尘天气过程.具有出现频率高、发生强度大、影响范围广等3个特点.

(2)沙尘天气1999年9次,2000年14次,2001年18次,2002年12次,“沙尘暴”天气逐年加剧说明我国北方植被受到了严重破坏.

(3)在我国西北地区,植被覆盖率本来就不高,贫穷的西北人民还想靠过度放牧、挖甘草、搂发菜、开矿发财,这些掠夺性的破坏行为更加剧了这一地区的沙尘暴灾害.裸露的土地很容易被大风卷起形成沙尘暴甚至强沙尘暴.人口膨胀导致的过度开发自然资源、过量砍伐森林、过度开垦土地、过度放牧是沙尘暴频发的主要原因.

(4)草地面积减少,土壤蓄水能力降低,植被遭破坏使土壤裸露并荒漠,有风便起风沙,森林面积减少,防风固沙能力下降,导致出现沙尘暴.

(5)治理沙尘暴的措施有:造防护林,保护草原、控制载畜量;退耕还林、还草等增加植被覆盖率.

故答案为:

(1)范围广;强度大;频率高;

(2)植被(或森林草原);

(3)A;

(4)草地面积减少,土壤蓄水能力降低,植被遭破坏使土壤裸露并荒漠,有风便起风沙,森林面积减少,防风沙能力下降;

(5)造防护林,保护草原、控制载畜量;退耕还林、还草等.

单项选择题
单项选择题

The elephant was lying heavily on its side, fast asleep. A few dogs started barking at it. The elephant woke up in a terrible anger: it chased the dogs into the village where they ran for safety. That didn’ t stop the elephant. It destroyed a dozen houses and injured several people. The villagers were scared and angry. Then someone suggested calling Parbati, the elephant princess.

Parbati Barua’s father was a hunter of tigers and an elephant tamer. He taught Parbati to ride an elephant before she could even walk. He also taught her the dangerous art of the elephant round-up—how to catch wild elephants.

Parbati hasn’ t always lived in the jungle. After a happy childhood hunting with her father, she was sent to boarding school in the city. But Parbati never got used to being there and many years later she went back to her old fife. "Life in the city is too dull. Catching elephants is an adventure and the excitement lasts for days after the chose," she says.

But Parbati doesn’ t catch elephants just for fun. "My work," she says, "is to rescue man from elephants, and to keep elephants safe from man. " And this is exactly what Parbati has been doing for many years. Increasingly, the Indian elephant is angry: for many years, illegal hunters have at- tacked it and its home in the jungle has been reduced to small pieces of land. It is now fighting back. Whenever wild elephants enter a tea garden or a village, Parbati is called to guide the animals back to the jungle before they can kill.

The work of an elephant tamer also involves love and devotion. A good elephant tamer will spend hours a day singing love songs to a newly captured elephant. "Eventually they grow to love their tamers and never forget them. They are also more loyal than humans. " She said, as she climbed up one of her elephants and sat on the giant, happy animal. An elephant princess indeed!

The passage starts with an elephant story in order to explain that in India ()

A. people easily fall victim to elephants’ attacks

B. the man-elephant relationship is getting worse

C. elephant tamers are in short supply

D. dogs are as powerful as elephants