科普文章哈。从IRS抄来的，绝对正确。：）
Refundable Tax Credits
A refundable tax credit is a tax credit that can reduce your tax liability below zero (0). Because it is possible to receive a refund from this type of credit, they're referred to as refundable.
Refundable tax credits include:
- Earned Income Credit
- Adoption Credit(now refundable for adoptions finalized in 2010 or 2011, or for carryforwards)
- First-time Homebuyer Credit
- Excess Social Security Credit
- Additional Child Tax Credit
- Health Coverage Tax Credit
- American Opportunity Credit- partly refundable
再加一句，refundable tax credit 都是鼓励穷人的，收入过了5万基本上就拿不到了。拿不到也别丧气，说明你是有钱人。：）
