根据汉语提示或英语解释，写出各单词的正确形式，每空填一词。
1. It is about 9 years since Hong Kong's _____ (coming back) to China.
2. Something should be done to protect the _____ (环境) in our hometown.
3. Can you _____ (描述) what he looks like?
4. The writer wrote the workers' _____ (everyday) lives in the book.
5. There is a robot _____ (展览) in the hall.
6. Now the student has _____ (get to know and understand something) that he was wrong.
7. He is very young, but he has a rich _____ (知识) of computers.
8. Beijing is the second biggest city and the _____ (文化的) centre of China.
