Was heißt »Volljähriger« auf Englisch?

Das Substantiv »Volljähriger« lässt sich wie folgt von Deutsch auf Englisch übersetzen:

Antonyme

As an adult, Mary was interested in many things which had bored her at school.
In the 15th century, Portugal was a major colonial power.
Zurich is considered a major financial hub.
The major roads are overburdened with lorries.
You are the only adult here.
Russia is a major naval power.
Russia is a major sea power.
The average adult has about five liters of blood in the body.
I've enrolled on a Spanish course at the adult education centre.
Merkel has led Europe’s biggest economy for the past 16 years and has played a major role in Europe and on the global stage.
I may look like an adult, but I'm not.
The Caro-Kann defense (1. e4 c6) is an opening used by major Grand Masters around the world.
He succeeded in spite of major difficulties.
He succeeded in spite of major hurdles.
She learned to read as an adult because she wanted to be able to read to her young son.
Forests help provide the air we breathe and play a major role in providing clean water.
Tom looks like an adult.
An adult male elephant can be more than three meters tall and weigh more than six tons.
Hubble played a major role in discovering dark energy.
Louis XIV of France is said to have taken only two baths in his adult lifetime–both times recommended by his doctors.