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问题 选择题

下列说法正确的是（　　）

A．实验室用块状石灰石和稀硫酸制二氧化碳

B．实验室用高锰酸钾分解制氧气

C．电解水获得氢气和氧气的体积比为1：2

D．工业上用烧碱制备纯碱

答案

A、因实验室制取二氧化碳是利用碳酸钙与盐酸反应来制取，若选用硫酸，因硫酸钙微溶，包裹在碳酸钙的表面将阻止反应的进行，故A错误；

B、因高锰酸钾中含有氧元素，由氧元素守恒可知，高锰酸钾分解能制取氧气，故B正确；

C、因电解水时得到的氢气的体积大，则氢气和氧气的体积比为2：1，故C错误；

D、因烧碱比纯碱价格高，一般利用纯碱与熟石灰来制取烧碱，故D错误；

故选B．

单项选择题

An eight-year-old child heard her parents talking about her little brother. All she knew was that he was very sick and they had no money left. When she heard her daddy say to her (1) mother," (2) a miracle can save him now", the little girl went to her bedroom and took out her piggy bank. She (3) all the change out on the floor and counted it carefully. Then she (4) her way six blocks to the drugstore.

"And what do you want" asked the shopkeeper. "It’s (5) my little brother," the girl answered back. "He’s really, really sick and I want to buy a (6) . His name is Andrew and he has something (7) growing inside his head and my daddy says only a miracle can save him. " "We don’t (8) miracles here, child. I’m sorry." the chemist said, smiling (9) at the little girl.

In the shop was a (10) customer. He stooped down and asked the little girl, "What kind of miracle does your brother (11) " "I don’t know," she replied. "He’s really sick and mommy says he needs (12) . But my daddy can’t pay for it, so I have brought my (13) .""How much do you have" asked the man. "One dollar and eleven cents, (14) I can try and get some more," she answered quietly. "Well, what a coincidence," smiled the man. "A dollar and eleven cents—the (15) price of a miracle for little brothers. (16) me to where you live. I want to see your brother and (17) your parents. "

That well-dressed man was Dr Carlton Armp, a doctor. The operation was completed without any (18) and it wasn’t long before Andrew was (19) again. The little girl was happy. She knew exactly how much the miracle cost—one dollar and eleven cents—also the (20) of a little child.

3（）

A．drew

B．pulled

C．put

D．poured
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问答题 案例分析题

心电图诊断为
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