问题 不定项选择题

已知在含氧酸中只有H原子与O原子相连时,才能在水溶液中电离出H+。次磷酸与足量的氢氧化钠溶液 反应的产物为NaH2PO2,又知浓度均为0.1mol/L的次磷酸(H3PO2)与盐酸相比前者导电能力弱。据此判断下列说法中正确的是[ ]

A.次磷酸是二元弱酸,在水中的电离方程式为H3PO2H++H2PO2-

B.次磷酸的结构中,只有一个H原子与O原子直接相连

C.次磷酸是一元弱酸,在水中的电离方程式为H3PO2H++H2PO2-

D.0. 1mol/L次磷酸可与等体积的0.2mol/L氢氧化钠溶液完全中和

答案

BC

阅读理解

阅读表达

       A man was exploring(探测)some caves on the beach.ln one of them he found a bag with many

clay(泥)balls. It seemed that someone had made them and had left them there. They interested the

man very much,so he took the bag out of the cave with him.

       As he was walking down the beach,he threw one clay ball at a time into the sea as far as he could.

       He didn't think much of it until he dropped one of the balls. The clay ball broke,and a beautiful,

precious stone came out of it.Excited,the man started breaking the other clay balls. He found that they

all had similar treasure in them. He found treasure that is worth thousands of dollars in the 20 left clay

balls.

       He regretted that he had thrown away about 50 0r 60 of the clay balls into the sea. He could have

had a lot more money.

       This is just like what happens in life. We look at people,maybe even ourselves,only from the outside. The outside doesn't look beautiful,so we pay no attention to them and only envy(羡慕)people who are

beautiful or famous. We don't notice that we may have missed the treasure inside those people.

1. 将文中画线的句子翻译成汉语。

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2. 文中画线的单词precious的汉语意思是:

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3. How should we look at people including ourselves?

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4. 从文中找出与下面句意义相近的句子。    

       While he was walking along the beach,he threw one clay ball each time into the sea as far as he could throw.                                                          

5. The best title for the passage is"              ".

A. Clay Balls      

B. Hidden Treasure      

C. Treasure Worth Thousands of  Dollars

单项选择题