题干

下列有关说法正确的是(   )

A:石油的组成元素主要是碳和氧,同时还含有少量的硫、氢、氮等

B:煤是由有机物和无机物所组成的复杂的混合物,煤中含量最高的元素是氢

C:甲烷在一定条件下可被氧化,生成的混合气体在催化剂和一定压强、温度下能合成甲醇(CH3OH)

D:所有烷烃中都存在碳碳单键

上一题 下一题 0.0难度 选择题 更新时间:2018-08-20 05:38:27

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C

同类题4

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    Our room was on the second floor but you could still hear the roar of the ocean and see the stars at night. I used to take long walks along the water. The food in town was wonderful and the people were very friendly. The area was very quiet and peaceful, and fairly deserted.

    The last evening of our vacation, however, we all heard strange footsteps following closely behind us as we were walking up to our room in the holiday centre. We turned around and noticed a fairly young man moving very rapidly across the beach and getting closer to us. He was tall and wore a baseball cap. We couldn't see his face and he was approaching us very rapidly. The man's actions made my dad very nervous. Dad warned us that we'd better try to make it to our hotel room as quickly as possible. I didn't like my dad's voice; I could hear fear in it. It was late and we were all alone. We didn't have any cell phones on us. I never saw Dad as worried as he was then and I knew that something was terribly wrong. The sense of fear started to overwhelm Mom and me. We had had such a good time in town. Now, the night was rapidly turning into a dangerous situation.

    We could hear the man's footsteps getting closer. Dad's face was almost pale. The so-called intruder (侵入者) had moved nearer and nearer when all of a sudden, the nearby vending (自动贩卖) machine started going crazy and spitting out cans of soda! The noise actually scared the intruder and he ran out of sight. My parents were shaking, but we all turned around to see who had put money into the vending machine downstairs, and actually saved us, but no one was around at all. Not a soul.

    It's one vacation I will never forget.

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