=>
1/
1. of
2. unless
3. which
4. yours
5. does
6. at
2/
1. C she didn't live in a small flat
2. E to get in touch with the manager of the company
3. A wasting water, we will have a shortage of water in somce decades
4. F going to school by bike to save energy
5. B we gave our teachers red roses that were very beautiful
6. D what aspects of learning English I found most difficult
3/
1. eruption
2. compulsory
3. badly
4. natural
5. not to stay
6. didn't work
7. has had
8. would tell
4/
1. up -> off
2. will -> would
5/
1. Lan is the most intelligent in my class.
2. The man who is standing over there is my uncle.