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下列有关棱柱的说法：

①棱柱的所有的面都是平的；

②棱柱的所有的棱长都相等；

③棱柱的所有的侧面都是长方形或正方形；

④棱柱的侧面的个数与底面的边数相等；

⑤棱柱的上、下底面形状、大小相等．

正确的有______．

答案

根据棱柱是多面体知棱柱的所有的面都是平的；①正确，

棱柱的所有的棱长不一定都相等；②不正确，

棱柱的所有的侧面都是长方形或正方形或是平行四边形，③不正确，

棱柱的侧面的个数与底面的边数相等，④正确，

棱柱的上、下底面是两个全等的多边形，形状、大小相等，⑤正确

故答案为：①④⑤

单项选择题

Young girls at high risk for depression appear to have a malfunctioning reward system in their brains, a new study suggests. The finding comes from research that (1) a high-risk group of 13 girls, aged 10 to 14, who were not depressed but had mothers who (2) recurrent depression and a low-risk group of 13 girls with no (3) or family history of depression. Both groups were given MRI brain (4) while completing a task that could (5) either reward or punishment.

(6) with girls in the low-risk group, those in the high-risk group had (7) neural responses during both anticipation and receipt of the reward. (8) , the high-risk girls showed no (9) in an area of the brain called the dorsal anterior cingulated cortex (背侧前扣带皮质), believed to play a role in (10) past experiences to assist learning.

The high-risk girls did have greater activation of this brain area (11) receiving punishment, compared with the other girls. The researchers said that this suggests that high-risk girls have easier time (12) information about loss and punishment than information about reward and pleasure.

"Considered together with reduced activation in the striatal (纹状体的) areas commonly observed (13) reward, it seems that the reward-processing system is critically (14) in daughters who are at elevated risk for depression, (15) they have not yet experienced a depressive (16) ," wrote Ian H. Gotlib, of Stanford University, and his colleagues. " (17) , longitudinal studies are needed to determine whether the anomalous activations (18) in this study during the processing of (19) and losses are associated with the (20) onset of depression," they concluded. The study was published in the April of the Archives of General Psychiatry.

4（）

A.explorations

B.examinations

C.detections

D.scans
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单项选择题

什么是具有生物相容性、经过安全评价且应用于药物制剂的一类高分子辅料（）

A.药用高分子材料

B.高分子材料

C.任何材料

D.药用材料
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