Stack Exchange network consists of 178 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
View all activity pages
when 双 is used, it usually means the thing is born/created/made that way.
when 对 is used, it usually means one match the other in some way.
了解 is more like "Known"
理解 is more like "Understand"