活力的名词形式activity。
active
adj.(尤指体力上)忙碌的，活跃的;积极的;定期进行的;起作用的
n.主动语态
比较级 more active
最高级 most active
You are expected to be an active participant.
你应该成为积极的参与者。
In spite of his age, he still leads an active life.
尽管年事已高，他依旧过着一种忙碌的生活。
She takes an active part in school life.
她积极参加学校活动。
