吸收塔液位偏低时，怎样处理。
参考答案：
1）工艺水补水
2）及时补充电石渣浆液
3）冲洗除雾器
4）吸收塔底坑补水。
目前工程中常用的切断机械的型号有GJ5-40型、QJ40-1型、GJ5Y-32型等三种。( )
We thought of selling this old furniture, but we've decided to ____ it. It might be valuable.
A. hold on to
B. keep up with
C. turn to
D. look after
