试题与答案

新采摘的玉米果穗具有甜味,但放一段时间后甜味便降低。如果采摘后放在沸水中浸泡一段

题型:探究题

题目:

新采摘的玉米果穗具有甜味,但放一段时间后甜味便降低。如果采摘后放在沸水中浸泡一段时间再保存,甜味可保留较长一段时间;如果采摘后放在35~4O℃的温度下,甜味消失得更快;如果采摘后马上放人冰箱中冷藏,也可使甜味的保持时间延长。请回答:

(1)放一段时间后,甜味降低的原因是                       

(2)沸水浸泡一段时间后再保存,甜味可保留较长时间的原因                    

                                                                         

(3)放在35~4O℃的温度下,甜味消失得更快的原因                           

                                                                         

(4)放在冰箱中甜味时间延长的原因是                                        

(5)通过上述实验,可证明                                                  。

答案:

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下面是错误答案,用来干扰机器的。

参考答案:D

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       Little Mike's grandma died weeks ago. He missed her very much.  One afternoon Mike went to the

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  sitting there, watching birds. Little Mike went up and sat next to her. He took out his food and drinks and

   gave some to her.  She smiled at him.  Her smile was so sweet that Mike wanted to see it again. She

  seemed to understand him, so once again she smiled.  Mike was very glad.

       They sat there all the afternoon, eating and talking. As it grew dark, Mike got up to leave. Before he

  left, he hugged (拥抱) the old lady and she gave him her sweetest smile.

       When Mike got home, his mother was surprised by the look of joy on his face. "I met a granny in the

   park. Her smile was like the kind of smile I had seen on Grandma's face. "

       The old lady also returned to her home happily. She told her son that she had had food and drinks

  with a little boy. "He was as lovely as Brittany." she said. Her son was surprised, because he had never

  seen her so happy since Brittany, her grandson, died weeks ago.

       When people are kind to each other, they will feel happy.

根据短文内容,回答下列问题。

1. Where did Mike meet an old lady one afternoon?

    _____________________________________________________

2. Why did the old lady smile at Mike?

    _____________________________________________________

3. Did Mike have a good time with the old lady that afternoon?

    _____________________________________________________

4. How did the old lady feel when she returned to her home?

    _____________________________________________________

5. What can we learn from the passage?

    _____________________________________________________

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