youthfully

adv.in a youthful manner

"he is still youthfully enthusiastic"

1. She danced youthfully, as if she were still in her twenties.
   她跳舞时充满青春活力，仿佛她还是二十岁左右。
2. He greeted everyone youthfully, with a big smile and an enthusiastic attitude.
   他以一种年轻的方式与每个人打招呼，带着灿烂的笑容和热情的态度。