1. I know from my own __________(经验) how difficult the work can be.
2. The children all rose up when the __________ (校长)came in.
3. I __________ (敬重)him for his diligence.
4. The __________ (平均的)age of the boys in this class is fifteen.
5. Let’s join hands and __________ (奋斗)together.
