圆锥的底面半径是1,侧面积是2π,则这个圆锥的侧面展开图的圆心角为  .

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问题:

圆锥的底面半径是1,侧面积是2π,则这个圆锥的侧面展开图的圆心角为   

考点:圆的认识正多边形和圆(内角,外角,中心角,边心距,边长,周长,面积的计算)弧长的计算扇形面积的计算
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Every year thousands of people get hurt or die when they are crossing the road. Most of these people are old people and children. Old people often get hurt or die because they can’t see or hear very well. Children usually meet with accidents because of their carelessness. They forgot to look and listen before they cross the road.

How can we lessen (减少) traffic accidents? All of us must obey the traffic rules. For the drivers, they shouldn’t drive too fast. If they drive too fast, it will be very difficult to stop the cars in a very short time. For the pedestrians (行人), it’s very important to be careful when they are walking on the road. Therefore, when we walk across the road, we must try to walk along the pavements(人行道). We must stop and look both ways before crossing the road. Look left first, next look right, then look left again. Only when we are sure that the road is clear, we can cross it. The right way to cross the road is to walk quickly. It’s not safe to run. If people run across the road, they may fall down. Teens(青少年) should try to help children, old people or blind people to cross the road, and never play in the street.

小题1:Thousands of people get hurt or die when they are crossing the road every year, most of them are ______.

A.children and drivers

B.old people and children

C.old people and blind people

D.teens and drivers小题2:To lessen traffic accidents, we shouldn’t ______.

A.run quickly

B.walk quickly

C.be sure that the road is clear

D.look left, look right and look left again小题3: According to the passage, we know that ______ will be safe.

A.driving too fast

B.running across the road

C.walking alone the pavements

D.playing in the street小题4: Why do old people often get hurt or die when they are crossing the road?

A.Because they don’t look and listen.

B.Because they walk too fast.

C.Because they are not careful.

D.Because they can’t see or hear very well.小题5: What is the main idea of this passage?

A.Never play in the street.

B.Being safe in the street.

C.Look and listen before we cross the road

D..Stop and look both ways before crossing the road.

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扁平足

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对于血栓性静脉炎的处理,正确的是

A.口服抗凝药物

B.输血

C.局部按摩

D.患部输入抗生素溶液

E.患肢多活动,促进局部血液循环

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一个成功的商标作为主品牌,涵盖企业的系列产品,同时给不同商品加附一个生动新颖而有魅力的副品牌。

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从管理运行方面论述目前导致灌区土壤环境恶化的原因。

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