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问题 选择题

任何经济发展模式(体制)的出现,都有一定的时代性,同一经济发展模式（体制）在不同历史时期所起到的作用是不同的。目前已经证明了这一观点的是 

①苏俄（联）的新经济政策  ②苏联高度集中的经济体制 ③国家垄断资本主义 ④中国特色社会主义市场经济

A．①②

B．②③

C．②③④

D．①②③④

答案

答案：B

题目分析：本题考查学生史料阅读及史实的再认和再现能力。题干强调的是任何经济政策都不是一尘不变的，据所学知②③符合题意，故选B。

阅读理解

阅读理解。

     During the cold winter days you may find it hard to wake up in the morning. It's warm and cozy

(舒适的) in your bed.

     In winter, many animals like to sleep, too. But their sleeps can be very long and deep. This kind of

sleep is called hibernation (冬眠). During this kind of sleep, their temperatures go down, and hearts beat

(跳动) slowly. They take very small breaths.

     Animals can hibernate for part or all of the winter. It's hard for them to find things to eat. When they

go to sleep, they don't need much food.

     Bears, hedgehogs (刺猬) and chipmunks (花栗鼠) go to sleep in their homes. Frogs and snakes

hibernate, too. Frogs move into the earth under water to keep themselves warm.

     Before they go to sleep, they eat a lot to get fat (脂肪). Some also keep food in their homes to eat later.

Bears are the biggest animals that hibernate. They often sleep in caves (山洞).

     Bears must eat a lot of things like nuts before going to sleep for a long time. They eat as much as 300

apples (that's the same as 60 hamburgers) each day for many weeks. They can eat for 20 hours in a day!

     Bears can go into a very deep sleep. It can last from three months to half a year. During that time they

do not eat, drink or go to the toilet. A mother bear can give birth to babies during her hibernation.

     Other animals sleep less. Sometimes they wake up to eat, or take a walk. Then they go to sleep again.

根据短文内容判断正(T)误(F)：

( )1. Hibernation is a the long and deep sleep of animals in winter.

( )2. During hibernation, animals don't breathe at all.

( )3. Bears eat lots of food before they hibernate in winter.

( )4. Bears don't go to the toilet during their hibernation.

( )5. Frogs hibernate in the Earth under water.

( )6. Mother bears can't give birth to babies during hibernation.

( )7. We can infer that fat is an important food for animals during hibernation.

( )8. Bears, hedgehogs, chipmunks, pigs and frogs hibernate.

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单项选择题

阅读下面的文章，回答下列问题：
据英国《泰晤士报》11月7日报道，英国科学家计划试验用患者自身干细胞来修复受损的心脏。科学家希望，在把干细胞注入患者血管后，它们能够发挥自身特点，对心脏肌肉起到修补作用。
在英国，心脏病病人被送入医院后一般会接受一种名为“血管重建术”的手术，具体而言，就是把一端装有小气囊的导管插入由于脂肪组织堆积而变窄的动脉，然后使气囊膨胀，以清除堵塞物并使动脉通畅。
这种手术能够提高患者存活率，但仍有相当一部分患者的心脏在血管短时间堵塞过程中受到严重伤害。现有治疗方法对这种心脏损伤效果不够理想，不少病人最终出现心力衰竭，也就是心脏无法以足够快的频率跳动供血，结果导致肺部充血、气短、下肢浮肿及肝脏肿大。
现在，英国科学家打算试验患者自身干细胞来修复受损的心脏。新的试验只是在这个手术的基础上增加一个步骤，即从病人髋骨提取骨髓，再从中分离出肌肉干细胞，随后通过导管注射入心脏。从心脏病发作到注入干细胞，期间最多不能超过5个小时。
干细胞是人体基本组成细胞之一，具有发育成各种人体组织的能力，其医疗研究的潜力巨大。与利用胚胎干细胞相比，利用病人自身干细胞有不少好处。首先，使用患者自身干细胞治疗自身疾病可以避免伦理问题。其次，由于是“就地取材”，所以可以在病人发病迅速提取，而且治疗费用相当低廉。其三，由于利用的是自身细胞，患者免疫系统不会出现排异反应。
但是，一些科学家对此持谨慎态度。他们认为，当人们还没有完成对干细胞的全面了解前，把其用于临床试验欠缺妥当。此外，由于使用成人自身的干细胞，这些细胞发育成其他人体组织细胞的能力不如胚胎干细胞那么强，因此，现在还不能断定这种疗法是否能起到预期效果。而且，人们曾经对基因疗法抱有现在对干细胞疗法相同的热情，但是基因疗法目前仍“阴云密布”。一位美国病人在使用病毒携带基因进入肺部时因副作用而死亡。
医学专家表示，如果伦敦的这次试验能够用较简便的方式限制心脏病发作造成的损失，当然值得高兴，但不过度乐观可能更明智一点。

关于“血管重建术”，下述说法不正确的是______。

A．血管重建术是一种治疗心脏病的常用手术

B．血管重建术通过插入动脉的气囊膨胀来清除堵塞物并使动脉通畅

C．血管重建术能够提高心脏病患者存活率

D．血管重建术可能导致肺部充血、气短、下肢浮肿及肝脏肿大
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