问题 单项选择题 A1/A2型题

下列不是藻酸盐类印模材料中填料的作用和特点的是()

A.增加藻酸盐凝胶的强度

B.难溶于水,也不参加化学反应

C.充实体积,增加硬度,提高抗压强度

D.增加溶胶的稠度,提高材料韧性

E.填料粒子越小,制取的印模精确度越高

答案

参考答案:D

解析:滑石粉、硅藻土等填料在印模材料中的作用是增加藻酸盐凝胶的强度,使制取的印模保持良好的形状稳定。填料是一些具有惰性的小粒子,难溶于水,也不参加化学反应。在材料中的作用是充实体积,增加硬度,提高抗压强度。填料粒子越小,制取的印模精确度越高。而硼砂、硅酸盐等增稠剂的作用是增加溶胶的稠度,提高材料韧性,调节印模材料的流动性,并且有一定加速凝固作用。

阅读理解

阅读理解。

 

     It was Christmas morning and she felt sorry. "Mr. Harriet, I'm so sorry to bother you today. I think you

 want a rest at Christmas like anybody else. "

     "Please don't worry about that," I said. "Which one is it this time?"

     "It's not one of the dogs. It's. . . Debbie. "

     "Debbie? She's at your house now?"

     "Yes… but there's something wrong. Please come quickly. "

     When I went to Mrs. Ainsworth's home, Debbie was there all right, but this time everything was

 different. She wasn't sitting in her usual place;  she was lying down quietly on her side, and close to her lay

  a little black kitten.

      I examined Debbie carefully while Mrs. Ainsworth looked at me. Her voice seemed to come from

 afar. "Is she ill,  Mr. Harriet?"

      "Yes… yes,  I'm afraid so. She is very ill. " I stood up. "There's really nothing you can do. I'm sorry. "

      Mrs. Ainsworth reached out and touched black Debbie's body. "Isn't it strange? She was dying and

 she brought her kitten here. And on Christmas Day. "

     Tears went down Mrs. Ainsworth's face and she was bright-eyed as she looked at me. "I've never had

 a cat before." She said.

     I smiled. "Well, it looks as though you've got one now. "

     "Debbie would be pleased. " She said.

      I nodded. "Yes,  she would. . . It was just a year ago that she came here,  wasn't it?"

     "That's right. " She looked at the kitten kindly. "The best Christmas present I have ever had. "

1. From the first paragraph, we mainly know_____.

    A. Mrs. Ainsworth was ill                

    B. Mrs. Ainsworth called Mr. Harriet

    C. Mrs. Ainsworth wasn't friendly            

    D. it was Christmas morning

2. Who was ill?

    A. Mrs. Ainsworth.                

    B. Mr. Harriet.

    C. Debbie.                        

    D. One of the dogs.

3. Mrs. Ainsworth's voice seemed to come from afar because _____.

    A. she worried about Debbie                    

    B. she was very ill

    C. she was afraid of Mr. Harriet                

    D. Debbie was dead

4. Which of the following statements is true?

    A. Debbie was one of Mrs. Ainsworth's dogs.

    B. Debbie left home after she sent her kitten to Mrs. Ainsworth.

    C. Debbie brought her kitten to Mrs. Ainsworth before she died.

    D. Mrs. Ainsworth would not like to look after the kitten.

5. The best title of the passage is _____.

    A. The Christmas Cat            

    B. She Tried Her Best

    C. Debbie Went Away            

    D. Mrs. Ainsworth

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