idiom. unit 4. knowing and understanding

know st inside out

(when it comes to geography) he knows his stuff

the book title has a familiar ring to it. i think i read it long time ago

i'm not sure if i know her, but the name rings a bell

dont have a clue (how to use this book)

dont have the faintest idea

dont have the foggiest idea

i cant for the life of me remember her name

i'm a bit out of touch WITH computers these days(i used to know, but dont know the development)

it doesnt ring ANY BELLS WITH me

put two and two together(concluded from the facts known)

get (hold of) the wrong end of the stick