did he realize】 what the festival really means to commemorat

did he realize】 what the festival really means to commemorate a famous Chinese poet and patriot
However,not until he visited China,witnessed the dragon boat racing and tried Zongzi,a traditional food made of glutinous rice and served during the festival,【【【did he realize】】】 what the festival really means to commemorate a famous Chinese poet and patriot,Qu Yuan,in Spring and Autumn Dynasty.
请问这里的 【【【did he realize】】】 是做强调的意思吗?
我们一般说强调不都是 i do see believe sth吗
最多也就是祈使句do come and see me some day!
这里的【【【did he realize】】】是什么意思的什么语法呢?麻烦大家指导一下小弟...