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问题 选择题
在匀强磁场中有一个原来静止的碳14原子核，它放射出的粒子与反冲核的径迹是两个相内切的圆，如图所示．那么碳14的衰变方程为（　　）

A．+→

B．→+

C．+→

D．→+

答案

答案：D

填空题

动词填空。

1. The little girl often _____ (teach) herself to do new things when she was young.

2. Driving to the centre of the city is faster than _____ (take) a bus.

3. My computer is broken, but my father doesn't agree _____ (buy) me a new one.

4. _____ (get) off the bus and we'll take the underground there.

5. Mr Wu and his students had a lot of fun _____ (travel) to South Hill.

6. Look, the students of Class One _____ (plan) to go on a school trip next week.

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单项选择题

心交感神经节后纤维释放的神经递质是

A．乙酰胆碱

B．去甲肾上腺素

C．血管紧张素Ⅱ

D．血管升压素
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