一物体做匀变速直线运动,下列说法中正确的是( ) A.物体的末速度一定与时间成正

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问题:

一物体做匀变速直线运动,下列说法中正确的是(  )

A.物体的末速度一定与时间成正比

B.物体的位移一定与时间的平方成正比

C.物体的速度在一定时间内发生的变化与这段时间成正比

D.若为匀加速运动,速度和位移都随时间增加;若为匀减速运动,速度和位移都随时间减小

考点:匀变速直线运动的速度与时间的关系匀变速直线运动的位移与时间的关系
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请阅读分析下列材料,回答问题

材料一:科学家做过这样一个实验。人们把红薯撒在海滩上使猕猴走出森林,来到海滩取食红薯。一只2岁的小猴破天荒地首先学会了把红薯放在水中洗干净再吃,后来,其它猴子也逐渐学会了这种处理红薯的方法。

材料二:黄面兀鹫迁徙于埃及和西班牙之间,它们在西班牙孵卵育雏。在埃及,黄面兀鹫喜欢吃那里的鸵鸟蛋,并可利用工具——石块把蛋砸开。科学家在西班牙把兀鹫刚孵化出来的雏鸟偷来进行封闭式的人工饲养,它们从来没见过鸵鸟蛋。当秋季来临,所有的兀鹫都返回埃及,科学家把人工饲养的这只兀鹫放飞,并在它停留的地上放上鸵鸟蛋,人们发现这只年轻的黄面兀鹫奇迹般地用石块砸开鸟蛋,并把它吃掉。

请你分析:

(1)材料一、材料二都说明的是动物的什么行为?

(2)从动物行为获得的途径来看:“材料一”所表达的猴子行为和“材料二”所表达的黄面兀鹫行为分别是属于动物的什么行为?

(3)“材料一”所表达的猴子行为是怎么获得的?

(4)“材料一”所表达的猴子行为对动物来说有何意义?

题型:选择题

莱姆病皮肤组织病理改变以__的出现有助于诊断。

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外国投资者对上市公司进行战略投资应符合( )要求。

A.以协议转让、上市公司定向发行新股方式以及国家法律法规规定的其他方式取得上市公司A股股份

B.投资可分期进行,首次投资完成后取得的股份比例不低于该公司已发行股份的20%,但特殊行业有特别规定或经相关主管部门批准的除外

C.取得的上市公司A股股份2年内不得转让

D.法律法规对外商投资持股比例有明确规定的行业,投资者持有股份比例应符合相关规定

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Office workers should know that long periods of sitting at your desk may be a killer. Scientists have shown a new threat from this lifestyle that they call  “muscular inactivity (肌肉迟钝)”.

Sitting still for long periods of time leads to the buildup of substances (物质) in the blood that are harmful to health. And exercise alone won’t drive them away.

Millions of people spend their days between car,office desk and the sofa in front of the TV. While the bad influences are well rocognized,it has been thought that they can be changed by regular trips to the gym or swimming pool.

Now researchers say that is not enough. In addition to regular exercise,office workers need to keep moving while they work,by making regular trips to the printer,coffee machine or to chat with workmates.

Elin Ekblom­Bak,an expert on health,says research shows long periods of sitting and lack (缺乏)  of “whole body muscular movement”  are strongly linked to obesity,heart disease and cancer,and a higher risk of death,regardless of (不管) whether they take enough exercise.

“Everyone knows about the health benefits of regular exercise. But what we haven’t realized before is that long­period sitting down carries an extra risk that cannot be dealt with by taking exercise,” Dr Ekblom­Bak said,adding that sitting still should be recognized as a risk to health.

“It is important to have a five­minute break from desk work every 45 minutes. Don’t email workmates—walk across the office to give them the message. Take a coffee break or put the printer in the next room. I am a desk worker and I try to do it. It is not difficult but sometimes you get lost in your work and you forget about it.”

However,more studies are needed to confirm the ill effects of sitting for too long and ways of fighting them. But at present they conclude that  “keep moving”  should be added to the advice to “keep exercising.”

小题1:Nowadays,many office workers wrongly think that________.

A.long periods of sitting has bad influences on them

B.regular exercise benefits them after long periods of sitting

C.they are living a lifestyle called “muscular inactivity”

D.it’s unfair for them to sit in the office for too long小题2:What does the author suggest office workers should do?

A.Chat with workmates often.

B.Send emails instead of chatting.

C.Keep moving in the office regularly.

D.Take more exercise after work.小题3:The last paragraph suggests that the result of the study is________.

A.scientific

B.uncertain

C.unbelievable

D.convincing小题4:What would be the best title for the passage?

A.A new threat :long­period sitting

B.Office workers should keep exercising

C.Taking exercise benefits a lot

D.Keep moving,it could save your life

题型:选择题

最早提出的数据建模方法是______。

A.E-R

B.IDEF1X

C.DFD

D.UML

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