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问题 选择题

在A+B═C+2D的化学反应中，18g的A和16g的B恰好完全反应生成28g的C，则反应生成的D的质量是（　　）

A．12g

B．6g

C．16g

D．32g

答案

根据质量守恒定律反应前后物质的质量不变可知：18g+16g=28g+D的质量，则D的质量=34g-28g=6g．

故选B

单项选择题

(C)


Is there anything more important than health I don’t think so. "Health is the greatest wealth," wise people say. You can’t be good at your studies or work well when you are ill.
If you have a headache, toothache, backache, earache or bad pain in the stomach, if you complain of a bad cough, if you run a high temperature and have a bad cold, or if you suffer from high or low blood pressure, I think you should go to the doctor.
The doctor will examine your throat, feel your pulse, test your blood pressure, take your temperature, sound your heart and lungs, test your eyes, check your teeth or have your chest Xrayed. After that, he will advise some treatment, or some medicine. The only thing you have to do is to follow his advice.
Speaking about doctor’s advice, I can’t help telling you a funny story.
An old gentleman came to see the doctor. The man was very ill. He told the doctor about his weakness, memory loss and serious problems with his heart and lungs. The doctor examined him and said there was no medicine for his disease.
He told his patient to go to a quiet place for a month and have a good rest. He also advised him to eat a lot of meat, drink two glasses of red wine every day and take long walks. In other words, the doctor advised him to follow the rule: "Eat at pleasure, drink with measure and enjoy life as it is." The doctor also said that if the man wanted to be well again, he shouldn’t smoke more than one cigarette a day.
A month later the gentleman came into the doctor’s office. He looked much more cheerful and much happier. He thanked the doctor and said that he had never felt a healthier man.
"But you know, doctor," the man went on saying, "it’s not easy to begin smoking at my age.\

From the last sentence of the passage, we learn the man ______ before the doctor told him not to smoke more than one cigarette a day.

A. was a heavy smoker

B. didn’t smoke so much
C. didn’t smoke


D. began to learn to smoke
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单项选择题 共用题干题

9个月小儿，牛乳喂养，未加辅食，近1个月来常腹泻，食欲减退，有异食癖，皮肤黏膜苍白，肝肋下2cm，脾肋下0.5cm，Hb70g/L，血涂片：血细胞大小不等，以小细胞为主。

该患儿最主要的护理问题是（）。

A.营养失调：低于机体需要量

B.体液不足

C.有感染的危险

D.气体交换受损

E.知识缺乏
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