1. Youth is an important period in the ________ (发展)of a person.
2. From the 1960s most people could expect to have a long life ________ (预期数额).
3. He holds an important ________ (位置)in that famous company.
4. ________ (人类) are destroying nature day by day and they will get punishment sooner or later.
5. The cost of living ________ (指数)of this city is increasing.
