炉膛或烟道发生爆炸，使设备遭到严重损坏时，为什么要紧急停炉？
参考答案：
炉膛或烟道内发生爆炸，使设备遭到严重损坏时，对人身和设备安全威胁很大，如不紧急停炉有可能把事故扩大，如造成炉墙开裂，大量冷空气进入使燃烧不稳；助燃油不停掉，火焰和高温烟气外冒，造成热工仪表测点和电缆烧坏；因水冷壁受热不均，严重时使水循环破坏，造成水冷壁爆破；若冷灰斗倒塌不能除灰和出焦，更严重威胁锅炉运行。
| 完形填空。 | ||||
| Everyone needs friends. But do you know 1 to find real friendship (友谊) and keep it? An American writer 2 Sally tells young students some good ways to find 3 . Sally says finding friendship is just like 4 a tree. You plant the seed (种子) and 5 it to make it grow. She says you should first choose someone 6 can be a good friend. It doesn't matter whether he has money or good looks. A good friend should be kind and 7 . If you have a bad day, a good friend should 8 your complaints (抱怨) and do his 9 to help you. If you want to make a friend, you should make each other 10 . But things cannot always be happy. 11 the best friends may have quarrels. What should you do when you 12 with your friend? You may try to have an honest talk with him when there is no one around. If he 13 want to talk, you can write a letter to tell him how you are feeling. Sally also tells us some small but important things, 14 example, celebrating your friend's success. Remember that friendship is the 15 important thing in your life. Life is great if you have friends! | ||||
|