underpin
/ˌʌndəˈpɪn/verb
(-pinned, -pinning)with obj.
1- support (a building or other structure) from below by laying a solid foundation below ground level or by substituting stronger for weaker materials加固（建筑物或其他）地下基础。
1.1
- support, justify, or form the basis for支持; 巩固, 构成…的基础：
the theme of honour underpinning the two books.
荣誉这一主题是这两本书的基调。