在反应中CaH2+2H2O=Ca(OH)2+2H2↑,下列叙述正确的是( ) ①

题型:选择题

问题:

在反应中CaH2+2H2O=Ca(OH)2+2H2↑,下列叙述正确的是(  )

①H2是氧化产物 ②H2是还原产物  ③H2是氧化产物又是还原产物④CaH2中氢元素既被氧化又被还原  ⑤生成1mol H2时,电子转移1mol⑥H2O是氧化剂.

A.②④⑤

B.③⑤⑥

C.①④⑥

D.②⑤⑥

考点:氧化还原反应的本质和特征氧化还原反应的定义氧化还原反应的计算
题型:选择题
已知数列{an}满足an+1=-an2+2an(n∈N*),且0<a1<1.
(1)用数学归纳法证明:0<an<1;
(2)若bn=lg(1-an),且a1=
9
10
,求无穷数列{
1
bn
}
所有项的和.
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中国古代园林对植物的处理讲究()。

A.姿色

B.颜色

C.香味

D.造型

E.象征意义

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为了检验球罐的强度、考核球罐组装焊接质量,以保证球罐承受设计压力不漏,应进行的试验是()。

A.气压试验

B.渗漏试验

C.水压试验

D.气密性试验

题型:选择题

作业中必须安装()的指重表或拉力计。

A、精良

B、一般

C、合格

D、优质

题型:选择题

Before you make friends, you have to decide who you want to be your friends. Most people like to have friends who like to do the same kind of things they do.

The quickest way to make a friend is to smile. When you smile, people think you are friendly and easy to talk to. It may not be easy at first to smile, but remember most people will stay away from a scared or angry looking face.

One easy way to start a conversation with someone is to say something nice about him. Think about how great you feel when someone says something nice to you. Doesn’t it make you want to keep talking to that person?

Ask your new friends questions about themselves. Who’s their favorite singer, where do they live, what do they do after school are all good questions to start a conversation. Make sure you have something to add to the conversation, too. When someone asks you a question, do have an answer for them. There’s nothing that will stop a conversation quicker than a shrug (耸肩) for an answer.

Kids who show an interest in other kids and who are kind and friendly make good friends. Remember, everyone wants to be around people who like to do similar things and people who are nice to them.

小题1:This passage gives us some advice on _________.

A.how to make friends

B.what kind of person you can make friends with

C.how to start a conversation

D.the importance of smile小题2:Most people like to make friends with those______.

A.who are sad every day.

B.who share the same interest

C.who are fond of talking

D.who say bad things to them小题3:According to the third paragraph, most people enjoy talking to one _______.

A.who is always smiling

B.who seems to be friendly

C.who praises them

D.who points out their shortcomings.小题4:The underlined (划线的)part in this passage means “_______”.

A.being very proud

B.making no answer

C.knowing nothing

D.not hoping to answer

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