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问题 选择题

下列反应属于氧化还原反应的是（  ）

A．CaCO3＋2HCl====CaCl2＋H2O＋CO2↑

B．2NaHCO3 Na2CO3＋H2O＋CO2↑

C．Cl2＋2NaOH===NaCl＋NaClO＋H2O

D．NaBr＋AgNO3===AgBr↓＋NaNO3

答案

答案：C

题目分析：凡是有元素化合价升降的反应都是氧化还原反应，所以选项C准确，A和D是复分解反应，B是碳酸氢钠的分解反应，都不是氧化还原反应，答案选C。

点评：准确标出有关元素的化合价是判断反应是不是氧化还原反应的关键，所以熟记常见元素的化合价尤为重要。

阅读理解

I have a good friend at home. Her name is Mimi. She is white and yellow. She is very cute. I play with her when(当……的时候) I have time. She likes fish very much. When she is behind (在……之后) the sofa or in her box, you can’t see her. When I sit on the sofa, she sits with me. In the evening I do my homework at my desk, and she is on the desk. At that time I put her down(放下). Then she sits next to me. Is she a good friend of mine?

小题1:Who is my good friend at home?

A．A boy.

B．A cat.

C．A fish.

D．A tiger.小题2:When she is in the box or behind the sofa, you ____.

A．can’t see her

B．like her

C．play with her

D．don’t like her小题3:When I do my homework, she ____.

A．does its homework

B．plays with a ball

C．sits on the sofa

D．sits on the desk小题4:We can see ____ in the room.

A．a sofa

B．a black cat

C．some good friends

D．a computer小题5:I do my homework ____.

A．in the morning

B．in the afternoon

C．in the evening

D．at noon
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单项选择题

从超声横切面观察，胰腺的形态最常见的是（）

A.蝌蚪形

B.哑铃形

C.腊肠形

D.马蹄形

E.环形
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