I will show you the door.
（你以为是）我送你到门口。(I will show you to the door.)
（但其实是）我想请你滚蛋。(actually: I want to ask you to get away.)
这句英文原意是「大门就在那里」，有对着某人下逐客令的意思，是很不客气的说法。例：Be quiet, or I will show you the door.（安静，否则我会叫你滚出去。）
送客正解：I will show you to the door.或I will walk you out.
Were you out to lunch?
（你以为是）你出去吃午餐了吗？(Did you eat yet?)
（但其实是）你是疯了吗？(actually: Are you insane?)
out to lunch是一组俚语用法，意指疯狂或心不在焉，摆明是在教训别人。例：It seems that you were out to lunch in class.（你上课时似乎心不在焉。）
问别人吃饱没，正解：Did you eat yet?
I am a confidence man.
（你以为是）我是个有自信的人。(I am a confident man.)
（但其实是）我是个骗子。(actually: I am a cheater.)
confidence是自信、信任没错，但confidence man却是一组俚语用法，专指诈骗钱财的骗子或诈欺者。例：We finally realized that he was a confidence man.（最终我们发现他是个骗子。）
有自信的人正解：I am a confident man.