选择关系:表示在两者间选择其一. or 或者 either-or- 不是--就是-- or else 否则 otherwise 否则-- You must hurry or you’l——青夏教育精英家教网—

选择关系:表示在两者间选择其一. or 或者 either-or- 不是--就是-- or else 否则 otherwise 否则-- You must hurry or you’ll be late. 你得赶快了.否则你会迟到. Put on your sweater, or else you will catch a cold. 穿上你的毛衣.否则你会感冒的. I went at once ; otherwise I would have missed him. 我立刻过去.否则就见不到他了. 【查看更多】

题目列表(包括答案和解析)

Cu的化合物在生活及科研中有重要作用，不同反应可制得不同状态的Cu₂O
（1）科学研究发现纳米级的Cu₂O可作为太阳光分解水的催化剂。
①在加热条件下用液态肼（N₂H₄）还原新制Cu（OH）₂可制备纳米级Cu₂O，同时放出N₂。当收集的N₂体积为3.36L（已换算为标准状况）时，可制备纳米级Cu₂O的质量为；

②一定温度下，在2 L密闭容器中加入纳米级Cu₂O并通入0.20 mol水蒸气，发生反应：

；测得20 min时O₂的物质的量为0.0016 mol，则前20 min的反应速率v（H₂O）= ；该温度下，反应的平衡常数表达式K= ；下图表示在t₁时刻达到平衡后，只改变一个条件又达到平衡的不同时段内，H₂的浓度随时间变化的情况，则t₁时平衡的移动方向为，t₂时改变的条件可能为；若以K₁、K₂、K₃分别表示t₁时刻起改变条件的三个时间段内的平衡常数，t₃时刻没有加入或减少体系中的任何物质，则K₁、K₂、K₃的关系为；
（2）已知：

ΔH＝－293kJ·mol^－1

ΔH＝－221kJ·mol^－1
请写出用足量炭粉还原CuO（s）制备Cu₂O（s）的热化学方程式；
（3）用电解法也可制备Cu₂O。原理如右上图所示，则阳极电极反应可以表示为。

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书面表达。

    根据下面所提供的信息,写一封信.
    内容提示:
    假定你是王海,写信给在武汉工作的父亲,先告诉他家里的情况,然后告诉他你的学习情况,期中考试有些学科比较好,个别学科上还有困难,表示在老师和同学们的帮助下在短时间内可以赶上其他同学.
Dear Dad,
_________________________________________________________________________________________________________________________
      Do write to me if you have time.
                                                                                                           Yours ,
                                                                                                           Wang Hai

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阅读下面短文，然后根据短文内容选择最佳答案。

　　Children are amazing language learners! They are able to pick up new languages quickly and easily, without any accent(口音)．Adults, on the other hand, have to study hard to learn another language, and then they usually never lose their native accents．Why? What makes children different?

　　One explanation(解释)has to do with the muscles(肌肉)that control the movement in our mouths．In our mouths, there are hundreds of muscles that control the movements of our tongue, lips, cheeks, and so on．In children, their muscles are still flexible(灵活的), so it is easier for them to move their mouths into new positions(位置)to make new sounds．In adults, the muscles are less flexible, so it's more difficult for them to make sounds that aren't in their native language．

　　Another explanation has to do with our brains．There are two sides to our brains－the left side and the right side．In adults, each side of our brain helps us to do different things．For example, the left side of our brain helps us to think through problems step by step, while the right side helps us to remember things we see, hear, and feel．In children, however, the brain isn't yet divided(在两者划分界线)into a left and right side．Some researchers believe that this helps children to be more flexible language learners．In other words, their brains are more open to differences in a new language．

(1)

According to the passage above, children learn languages ________ than adult．
[　　]
A．	more easily
B．	less easily
C．	more correctly
D．	much more slowly

(2)

The muscles in children's mouths are ________．This allows them to make new sounds easily．
[　　]
A．	long
B．	flexible
C．	different
D．	young

(3)

There are two sides to an adult brain, and each side helps to ________．
[　　]
A．	become flexible language learners
B．	think through problems
C．	make decisions
D．	do different things

(4)

A child's brain is ________．
[　　]
A．	divided into a left and a right side
B．	not vet divided into a left and a right side
C．	going to develop into a left-sided brain
D．	going to develop into a right-sided brain

(5)

Which one of the following statements is true?
[　　]
A．	It is hard for an adult to study a new language while not losing his native accent．
B．	Children can learn a language more easily because their brains develop very fast．
C．	Children can become flexible language learners when they grow up．
D．	Adult's brains are more open to different languages．

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It's Sunday tomorrow. We are going to watch a football match (比赛). It's between (在两者之间）a Japanese team and a Chinese team.

The football match is going to be at four o'clock in the afternoon. Our teachers, Mr Li and Mr Wang, are going to watch the football match with us. We are going there by bike. We think we can come back at about six in the evening.

根据短文内容选择正确答案

1． It's ______ tomorrow.

[　　]

A．a fine day　　　　　　　　B．Monday

C．Sunday　　　　　　　　　D．Saturday

2． We are going to watch ______.

[　　]

A． a footbal　　　　　　　　　　　　 B． a football match

C． a basketball match　　　　　 D． a basketball

3． It's between ______.

[　　]

A． a Japanese team and an American team

B． Japanese and Chinese

C． a Japanese team and a Chinese team

D． A Chinese team and an English team

4． The match is going to begin at _____.　　　

[　　]

A． six o'clock　　　　　　　　B． five o'clock

C． seven o'clock　　　　　　　D． four o'clock

5． _____ are going to watch thematch with us.

[　　]

A． Mr Li　　　　　　　　　　B． Mr Wang

C． Our teach　　　　　　　　 D． Mr Li and Mr Wang

6． We are going there _____.

[　　]

A． by bike　　　　　　　B．by bus

C．on foot　　　　　　　　　　　　　D．by train

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阅读理解

　　It's Sunday tomorrow. We are going to watch a football match (比赛). It's between (在两者之间) a Japanese team and a Chinese team.

　　The football match is going to be at four o'clock in the afternoon. Our teachers Mr Li and Mr Wang are going to watch the football match with us. We are going there by bike. We think we can come back at about six in the evening.

根据短文内容选择正确答案。

1．It's ________ tomorrow.

[　　]

A．a fine day

B．Monday

C．Sunday

D．Saturday

2．We are going to watch ________ .

[　　]

A．a football

B．a football match

C．a basketball match

D．a basketball

3．It's between ________ .

[　　]

A．a Japanese team and an American team

B．Japanese and Chinese

C．a Japanese team and a Chinese team

D．a Chinese team and an English team

4．The match is going to begin at ________ .

[　　]

A．six o'clock

B．five o'clock

C．seven o'clock

D．four o'clock

5．________ are going to watch the match with us.

[　　]

A．Mr Li

B．Mr Wang

C．Our teach

D．Mr Li and Mr Wang

6．We are going there ________ .

[　　]

A．by bike

B．by bus

C．on foot

D．by train

7．We are going to be back at ________ .

[　　]

A．night

B．about six

C．four

D．noon.

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