【Q】
English was taught by my friend.は以下のように２パターンに変化するとありましたが、この２パターンの使い分け、意味の違いは何でしょうか？
English was taught by my friend.
↓
English taught by my friend
English being taught by my friend

【A】
English taught by my friend　は　English is(was) taught by my friend.(受動態)の名詞化で　
English being taught by my friend　は　English is(was) being taught by my friend.(受動態・進行形)の名詞化です。