Adolescence /ˌæd

invent /ɪnˈvent/ verb [ T ] NEW DESIGN
1. to design and/or create something which has never been made before
The first safety razor was invented by company founder King C. Gillette in 1903.
maintain /meɪnˈteɪn/ verb [ T ] KEEP IN GOOD CONDITION
2. to keep a road, machine, building, etc. in good condition
A large house costs a lot to maintain.
The roads around the town have been very poorly maintained.
maintain /meɪnˈteɪn/ verb [ T ] CONTINUE TO HAVE
1. to continue to have; to keep in existence, or not allow to become less
The army has been brought in to maintain order in the region.
We have standards to maintain.
Despite living in different countries, the two families have maintained close links .
The film has maintained its position as the critics' favourite for another year.