阅读短文，根据首字母填空。

     One day, John 1. s____ to his mother, "I am going to 2. p____ in the snow." "Okay." said his

mother. "3. P____ on your jacket, boots and mitts." "Don't 4. f____ your hat!" said 5. h____ mother.

John put on his hat. He played in the 6. s____. He 7. m____ a big snowman. He loved 8. h____

snowman. He played 9. w____ the snowman. He 10. h____ a good time.

钢在加热时，常见的加热缺陷有哪些？哪一种缺陷使轧件尺寸不精、确板型不好？