“主动帮忙”常见的英文表达有 offer to help voluntarily 或 take the initiative to help。
offer to help voluntarily 强调主动提出且是自愿地提供帮助。例如：He always offers to help voluntarily when others are in trouble.（当别人遇到困难时，他总是主动帮忙。）
take the initiative to help 突出主动采取行动去帮助。例如：She took the initiative to help the new colleague adapt to the work environment.（她主动帮忙让新同事适应工作环境 。）