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问题 多选题

t℃时，将100g某物质A的溶液蒸发掉10g水，恢复至t℃，析出2.5g晶体，再蒸发掉10g水，恢复至t℃，析出7.5g晶体．下列说法中不正确的是（　　）

A．t℃时原溶液是不饱和溶液

B．若A是CuSO4，则7.5g晶体中含水2.7g

C．t℃时，A的溶解度为75g

D．原溶液中A的质量分数为40%

答案

ABCD

填空题

根据括号内的提示或首字母填词。

1. When he came to the _________ (拐角) of the street, he turned left .

2. Do you think __________ (大象) are the largest animals on land?

3. My brother is too young to look after _________ (他自己).

4. My friend Lily likes _________ (收集) football stickers very much.

5. The boy was _________ (惊讶的) to get the first place in the exam.

6. Wednesday is the f________ day of the week .

7. A train is going t_________ a tunnel.

8. Amy can listen to the teachers c________ in class.

9. They found the _________ (lose) child yesterday.

10. Jenny is a good girl because she is always very _________ (help) to others.

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单项选择题

有关触发活动的描述，不正确的是（）

A.触发活动是指动作电位后产生的除极活动，也称为后除极

B.若后除极的振幅增高并抵达阈值，便可引起反复激动

C.触发活动多发生于动作电位的2相

D.触发活动亦可导致持续性快速性心律失常

E.可见于局部出现儿茶酚胺浓度增高、心肌缺血再灌注、低血钾、高血钙及洋地黄中毒时
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