问题 问答题

A-B二元合金相图如图4-1所示。在固相不扩散、液相完全混合的条件下,水平放置的质量分数wB=40%的A-B二元合金溶液从左至右定向凝固成长为L的横截面均匀的合金棒。

画出该棒中B原子的浓度分布曲线。

答案

参考答案:如图4-6b所示。

阅读理解

阅读理解。

       One day when Jack was walking in the park, he saw Sue, a friend of his, sitting on a bench with a dog beside her. The dog was looking up at Sue.

       Jack walked up to her and said, " Hello, Sue. How are you? May I sit and talk with you for a while?"

        "Of course. Please sit down," Sue said. Jack sat down next to Sue on the bench, and  they talked together. The dog went on looking at Sue. It seemed that it wanted some food.

     "That's a nice dog," Jack said, pointing at the animal. "Yes, he's handsome. He's strong and healthy. "

      "And hungry," Jack said. "He hasn't taken his eyes off you.  He thinks you've got some food for him. "

      "That's true,"  Sue said. " But I haven't. "  The two friends laughed and then Jack said, " Does your dog bite?"

      "No," Sue said. "He's never bitten anyone. He's always gentle and good-tempered. "

        Hearing this, Jack decided to pet the dog. He  put up his hand and touched the animal's head. At

once it jumped up and bit him. "Hey!" Jack shouted, "You said he didn't bite. "

      "No, I didn't," Sue answered. "You asked me if my dog bit, and I said no.  But that's not my dog. My dog's at home. "

根据短文内容判断正误,对的在括号中写T,错的在括号中写F。

(       )1. Jack and Sue didn't know each other before they met in the park.

(       )2. Jack asked to sit down next to Sue because he wanted to have a rest.

(       )3. Jack thought that the dog belonged to Sue.

(       )4. Sue's dog had never bitten strangers.

(       )5. The dog in the park wasn't gentle and good-tempered.

判断题