to do something secretly without their knowledge
彼らが知らないうちに何かをする (karera ga shiranai uchi ni nanika o suru)
"She was talking about me behind my back."
"彼女は私の背中の後ろで私について話していた。" (Kanojo wa **watashi no senaka no ushiro de** watashi ni tsuite hanashite ita.)
considering something from one's own perspective
to feel very proud and confident
You can count on my support.
to prepare the body or mind for activity
to share similar thoughts and feelings
To pursue a mistaken or misguided course of action.
