问题 选择题

逻辑推理是化学学习常用的思维方法。下列推理正确的是

A.酸性溶液的pH都小于7,所以酸溶液pH一定小于7

B.有机物都含碳元素,所以含碳元素的化合物都是有机物

C.水是纯净物,所以海水也是纯净物

D.中和反应有盐和水生成,因此有盐和水生成的反应一定是中和反应

答案

答案:A

选A。酸性溶液既包括酸溶液还有酸性盐溶液;少数含碳元素的化合物,如一氧化碳、二氧化碳和碳酸钙等具有无机物的特点,属于无机物;海水中含有大量可溶性物质属于混合物;酸和金属氧化物反应生成盐和水、碱和一些非金属氧化物反应也生成盐和水,但不属于中和反应。

阅读理解

阅读理解。

    A farmer had a cow. He took very good care of this cow and one day when it was ill. He was very

worried. He telephoned the vet. 

    "What's the problem?" The vet asked him when he arrived.

    "My cow is ill." the farmer said. "I don't know what's the matter with her. She's lying down and won't

eat. She's making a strange noise."

    The vet looked over the cow. "She's certainly ill, "he said, "and she needs to take some very strong

medicine."

     He took a bottle out of his box, put two pills into his hand and said, "The pills should make her better."

     "How should I give them to her?" the farmer asked.

     The vet gave him a tube (管子) and said, "Put this tube in her mouth, then put the pills in the tube and

blow. That'll make it."

     The next day the vet came to the farm again. The farmer was sitting outside his house and looked more

worried.

     "How's your cow?" the vet asked. 

     "No change," the farmer said. "and I'm feeling very strange myself." 

     "Oh?" the vet said. "Why?"

     "I did what you said," the farmer answered. "I put the tube in the cow's mouth and then put two pills

down it."

     "And?" the vet asked.

     "The cow blew first." the farmer said.

1.In the story, the vet must be ______. [ ]

A.the farmer's friend

B.a milk factory

C.a hospital for cows

D.a doctor for animals

2.The farmer asked the vet for help when his cow            .[ ]

A.was ill

B.didn't eat the pills

C.couldn't make any noise

D.couldn't lie down

3.What medicine did the vet give the farmer? [ ]

A.Two pills.

B.A long tube.

C.Bottle of pills.

D.A small box.

4.The vet taught the farmer how ______.[ ]

A.to blow the tube

B.to make the cow take the pills

C.to take the medicine

D.to put the tube in his mouth

5.Which of the following is true? [ ]

A.The farmer ate the pills himself.

B.The cow got better after taking the medicine.

C.The vet came to help farmer change the cow the next day.

D.The farmer waited for me vet outside his house the next day.

单项选择题