Do you know what that means?正确
在Do you know / Can you tell me 这类起句的提问句型中,后面从句必须是陈述句语序.
Do you know...
What does that mean ...
都属于问句形式,不能串在一块儿,what/where/when/how/who 这些词后面的句子必须改变.
例如：
你可以告诉我吗 Can you tell me...
他是谁 Who is he?
你可以告诉我他是谁吗?Can you tell me who (he is)
如果仍不明白欢迎追问.