What do you mean by that?
それはどういうこと[意味]ですか
What do you mean?
どういうこと?
What [((略式))How] do you mean?
どういう意味[こと]なの
What do you propose to do [doing] with that creature?
その動物をどうするつもりですか
What do you reckon to this?
これについて何か意見は?
What do you say to a cup of tea [giving it a try]?
紅茶は[やってみたら]どう?
What do you take me for?
私をどう思う?
What do you think of him?
彼のことをどう思いますか
What do you think of [about] that?
(自慢して)どうだ(,すごいだろ)
What do you think will happen?
何が起こると思いますか