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问题 单项选择题

造成肺心病肺动脉高压最重要的原因是

A．缺氧

B．血容量增加

C．二氧化碳潴留

D．毛细血管床减少

E．血液黏稠度增加

答案

参考答案：A

填空题

选词填空，每空一词。

                           since, for, from

1. He has lived in Nanjing _____ the year before last.

2. I've known him _____ we were children.

3. She waited me _____ 8 till 9 at the gate.

4. Our teacher has studied Japanese _____ three years.

5. We study at school _____ Monday to Friday.

6. She has been away from the city _____ about ten years.

7. It's about ten years _____ she left the city.
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问答题

如图甲是 * * 同学为学校办公楼空调设计的自动控制装置，R是热敏电阻，其阻值随温度变化关系如下表格所示．已知继电器的线圈电阻R0=10Ω，左边电源电压为6V恒定不变．电流表O～30mA量程接入电路，如图乙是电流表表盘．当继电器线圈中的电流大于或等于15mA时，继电器的衔铁被吸合，右边空调电路正常工作．

（1）请说明该自动控制装置的工作过程．

（2）该同学将电流表改成了温度表，通过计算并标出表盘上25℃的位置．

温度t/℃0510l52025303540
电阻

R/Ω

600550500450420390360330300
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