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问题 单项选择题 A型题

关于卵圆窝的描述，正确的是（）。

A.卵圆窝位于心房的外侧壁

B.卵圆窝位于房间隔中下部，为胎儿时期卵圆孔闭合后遗留的遗迹

C.房间隔缺损一般不发生于卵圆窝处

D.卵圆窝处房壁最厚

E.卵圆窝面积较大，约占房间隔的2／3

答案

参考答案：B

解析：卵圆窝位于房间隔中下部，为胎儿时期卵圆孔闭合后遗留的遗迹。卵圆窝比较薄，是房间隔缺损的好发部位。

单项选择题

5岁儿童，畏寒、发热8 h，嗜睡3 h，于8月15日入院。查：体温40.5℃，脉搏120次/分，血压75 mmHg，发育、营养良好，浅昏迷，瞳孔等大，对光反应良好，面色苍白，四肢冷，未见淤点和淤斑，心、肺（－），腹软，克、布氏征（－），胸片（－）。为及时诊断，应立即进行哪些检查：（）

A．血常规

B．肛拭子或盐水灌肠镜检

C．脑脊液检查

D．大便培养

E．血培养
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单项选择题

Sedimentary rock hardens within the earth’s crust as layers of matter accumulate and the pressure of the layers above converts the layers below into rock. One particular layer of sedimentary rock that contains an unusual amount of the element iridium has been presented as support for a theory that a meteorite collided with the earth some sixty million years ago. Meteorites are rich in iridium compared to the earth’s crust, and geologists theorize that a meteorite’s collision with the earth raised a huge cloud of iridium-laden dust. The dust, they say, eventually settled to earth where it combined with other matter, and as new layers accumulated above it, it formed a layer of iridium-rich rock.
Which one of the following, if true, would counter the claim that the iridium-rich layer described in the passage is evidence for the meteorite collision theory

A．The huge dust cloud described in the passage would have blocked the transmission of sunlight and lowered the earth’s temperature.

B．A layer of sedimentary rock takes millions of years to harden.

C．Layers of sedimentary rock are used to determine the dates of prehistoric events whether or not they contain iridium.

D．Sixty million years ago there was a surge in volcanic activity in which the matter spewed from the volcanoes formed huge iridium-rich dust clouds.

E．(E) The iridium deposit occurred at about the same time that many animal species became extinct and some scientists have theorized that mass dinosaur extinctions were caused by a meteorite collision.
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