voluntary
单词辨析：
主要用于人或行为，强调主动去做某事，而非应征的、受强迫的，常含无任何报酬之意。
Mary is a voluntary helper.
玛丽是自愿帮忙的。
Another source of income is from voluntary contributions of the local people.
另一个收入来源是当地人的自愿捐献。
We must adhere to the principle of voluntary participation.
我们必须坚持自愿参加的原则。
强调做某事是自愿而乐意的、心甘情愿的，用于此义时只作表语，通常后接动词不定式。
How much is he willing to pay?
他愿意付多少钱？
I was very willing to give her the chance she needed.
我很愿意把她需要的机会给她。
The lawyer told me he was perfectly willing to help.
律师告诉我，他非常愿意帮忙。
相关例句：
He is still involved in voluntary work promoting local enterprise.
他仍在从事促进当地创业的志愿者工作。
Attention is drawn to a special voluntary course in Commercial French
一门特别的商务法语选修课引起了大家的关注。
Voluntary contributions to the Organization increased by61% in the last biennium.
在上一个双年度中，本组织获得的自愿捐款增长了61%。
UNICEF is funded entirely by the voluntary contributions of individuals, businesses, foundations and governments.
联合国儿童基金会完全由个人、商业、基金会及各国政府自愿捐款。
The scheme, due to begin next month, will be voluntary.
定于下个月开始实施的方案是自愿性质的。
Apna Arts has achieved more with voluntary workers in three years than most organisations with paid workers have achieved in ten
“我们”艺术中心依靠志愿者在3年内取得的成就超过了大多数雇用受薪员工的机构10年中取得的成绩。