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问题 名词解释

卫星的无摄运动

答案

参考答案：卫星在轨运动受到中心力和摄动力的影响。假设地球为匀质球体，其对卫星的引力称为中心力（质量集中于球体的中心）。中心力决定着卫星运动的基本规律和特征，此时卫星的运动称为无摄运动，由此所决定的卫星轨道可视为理想的轨道，又称卫星的无摄运动轨道。

多项选择题

关于慢性病筛查，下列说法正确的是（）

A.筛查分为整群筛查和选择性筛查

B.筛查相当于对慢性病的诊断

C.筛查一般在疾病的无症状期开始进行

D.筛查试验应符合快速、简便、经济、安全及真实可靠的标准

E.筛查有利于早发现、早诊断、早治疗
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单项选择题

What’s your earliest childhood memory Can you remember learning to walk Or talk The first time you heard thunder or watched a television program Adults seldom (1) events much earlier than the year or so before entering school, (2) children younger than three or four (3) retain any specific, personal experiences.

A variety of explanations have been (4) by psychologists for this "childhood amnesia". One argues that the hippo-campus; the region of the brain which is (5) for forming memories, does not mature until about the age of two. But the most popular theory (6) that, since adults don’t think like children, they cannot (7) childhood memories. Adults think in words, and their life memories are like stories or (8) one event follows (9) as in a novel or film. But when they search through their mental (10) for early childhood memories to add to this verbal life story, they don’t find any that fit the (11) . It’s like trying to find a Chinese word in an English dictionary.

Now psychologist Annette Simms of the New York State University offers a new (12) for childhood amnesia. She argues that there simply aren’t any early childhood memories to (13) . According to Dr. Simms, children need to learn to use someone else’s spoken description of their personal (14) in order to turn their own short-term, quickly forgotten (15) of them into long-term memories. In other (16) , children have to talk about their experiences and hear others talk about (17) --Mother talking about the afternoon (18) looking for seashells at the beach or Dad asking them about their day at Ocean Park. Without this (19) reinforcement, says Dr. Simms, children cannot form (20) memories of their personal experiences.

Notes: childhood amnesia 儿童失忆症。

18（）

A.taken

B.utilized

C.applied

D.spent
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