请简述汽轮机超负荷运行的危害。
参考答案：
1、由于进汽量增加，叶片上所承受的弯曲应力增加；同时隔板、静叶片所承受的应力与引起的挠度也增加；
2、由于进汽量增加，，轴向推力增加，使推力瓦乌金温度升高，严重时造成推力瓦块烧毁；
3、调速汽门开度达到接近极限的位置，油动机也到了最大行程附近，造成调速系统性能变坏，速度变动率与迟缓率都会增加，使运行的平稳性变坏
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| Lily is a little girl. She is not ① . She ② how to read or write. But her sister Jill is ③ . She is ten years old. She knows how to read and write. One day, Jill ④ her little sister in the room. She looks ⑤ the table. There ⑥ a pencil in ⑦ hand. She is writing. "What are you writing, Lily?" she asks. "I'm writing ⑧ my friend Rose. " " ⑨ how can you? You don't know how to write," says her sister. "Well," says Lily, "It doesn't matter. Rose doesn't know how to ⑩ , either. " |
| （ ）①A. at school （ ）②A. doesn't know （ ）③A. school girl （ ）④A. write （ ）⑤A. or （ ）⑥A. how （ ）⑦A. my （ ）⑧A. from （ ）⑨A. Or （ ）⑩A. dance | B. work B. know B. school girls B. reading B. under B. is B. their B. to B. So B. sing | C. study C. don't know C. boy student C. seeing C. at C. are C. his C. for C. But C. write | D. a student D. doesn't knows D. student girl D. sees D. in D. have D. her D. with D. And D. read |