PHRASE
一点儿也不知道;根本没什么概念
If you say that you haven't the foggiest or you haven't the foggiest idea, you are emphasizing that you do not know something.
例句
I did not have the foggiest idea what he meant...
我根本不知道他是什么意思。
'How often does it need to be changed?' — 'Haven't the foggiest.'
“大概要多久换一次呢?”——“我一点儿概念也没有。”