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【单选题】
兴奋性突触后电位是突触后膜对什么离子的通透性增加而引起的?
A.
钾离子和钙离子
B.
钠离子和钾离子，尤其是钾离子
C.
钠离子和钾离子，尤其钠离子
D.
钠离子和钙离子
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周、一个月
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【简答题】A．May I help you? B．What's wrong? C．I'm glad to see you.
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At a shop
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【单选题】丁烷分子中,以 C 2 与 C 3 之间的 σ 键为键轴所形成的 4 种构象异构体:( I )对位交叉式;( II )部分重叠式;( III )邻位交叉式;( IV )全重叠式 。 按能量由低到高排序正确的是:( )
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（ Ⅰ ）（ Ⅲ ）（ Ⅳ ）（ Ⅱ ）
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相关题目：
【单选题】塔式起重机主要部件和安全装置应进行经常性检查，每()不少于一次，并应有记录;使用周期超过()时，应进行一次全面检查，合格后方可继续使用。
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周、一个月
B.
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C.
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【单选题】听力原文：M: May I help you? W: Yes, I want to buy some shoes to replace the ones I'm wearing. M: What's wrong with them? W: They are too old and shabby. M: I can see they have simply been worn out. Would ...
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They were worn out.
B.
They were dirty.
C.
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D.
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【单选题】丁烷分子中,以C2与C3之间的σ键为键轴所形成的4种构象异构体: (I)对位交叉式;(II)部分重叠式;(III)邻位交叉式;(IV)全重叠式。按能量由低到高排序正确的是:
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【单选题】听力原文：M: Good morning, may I help you? W: Yes, I'm looking for a light blue sports jacket. Q: Where does the conversation take place? (10)
A.
At a shop
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At a restaurant
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At a cinema
D.
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查看完整题目与答案
【单选题】听力原文：W: Hello, University of Sidney. May I help you? M: Yes. I'm looking for information on courses in computer programming. W: Do you want a day or evening course? M: Well, it would have to be an eve...
A.
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B.
To inquire about the time of the lecture.
C.
To buy some computer books.
D.
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【单选题】丁烷分子中,以 C 2 与 C 3 之间的 σ 键为键轴所形成的 4 种构象异构体:( I )对位交叉式;( II )部分重叠式;( III )邻位交叉式;( IV )全重叠式 。 按能量由低到高排序正确的是:( )
A.
（ Ⅰ ）（ Ⅲ ）（ Ⅳ ）（ Ⅱ ）
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（ Ⅰ ）（ Ⅲ ）（ Ⅱ ）（ Ⅳ ）
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House waste collection
B.
Garbage collection times
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Recyclable materials
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Collection procedures
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