固定床、流化床和移动床主要使由于它们床层流体速度的不同来区别的。

七、短文改错（10分）

It was snowing hardly last Monday morning. Li Hua was at the bus stop, waited for Bus No.6 to go to school. In a while, a bus came and she got it. There were many passengers on the bus. Some were talking but some were looking out of the window. Suddenly the bus stopped. The driver turned around and said, “sorry. The bus has been broken down. Please get off and help push it.” When he heard this, Li Hua and the other passenger got off the bus. They worked hard together, pushed the bus forward. Soon the bus was running again. Both the passengers were smiling and the sun was shining.

第五套人民币1999年版20元纸币迎光观察可见一条明暗相间的安全线。

加味四苓散功效与作用

毫秒电雷管分为哪两种？

广义的保险