1. 认真的：serious 严肃的 | serious-minded 认真的 | seriously 认真地

2. 認真的人類眾生相：56151認真;介意;傷心成語英美片語成語to take\lay to heart | 56153認真的人類眾生相serious-minded | 56154認真談正事成語英美片語成語to come\get down to business

3. 热心的：serious 严肃的, 认真的 (形) | serious-minded 热心的 | seriously 严肃地; 当真地; 认真地; 严重地 (副)

adj

1. acting with or showing thought and good sense

e.g. a sensible young man

Synonym: thoughtful