主句:Facebook(主语)+ is credited with(谓动,被动语态)+ sparking the change(介宾)
时间状语从句:when it(主语)+ allowed (谓动)+outside programmers(宾语)+
to develop new features for the wildly popular social networking site(宾补).
句意:脸谱网(Facebook)这个红透半边天的社交网站允许外来程序设计师为其开发新功能,
因此众人称赞它为融发这项变革的火花.