V.
1. Mysteriously
2. independence
3. depth
4. challenging
5. investigation
6. maintainance
VI.
1. we try to reduce world population, it will continue to rise
2. be back until Friday
3. not to eat too much red meat
4. have some money now, I will lend you some
5. be banned
6. was written by the secretary was a long ungrammatical one.
Ex2
1. existence
2. challenging
3. independence
4. contribution
5. investigation
6. currently
7. mysterious
8. including