"Do you know what the best thing is"与"Do you know what is the best thing to do"这两个句子中,"is"的位置为什么不一样?

what do you know Do you know what Do you know what? Do you know what the ____ is today?-It's September 29th what do you know是什么意思? Do you know ,what's - What does “story” mean here?Do you know the difference between falling off the 2nd and 12th story? Do you know what he_____(do) now? If you know what will you do Do you know what I like you do you know what you said what you name Do you know me Do you know what they_______(代表）? Do you know what they are? what’s this( )English?Do you know? do you know what things come from What do you know about Halloween? What do you know about this university?