YOU SAID:
I don't get the concept of excersize.
INTO JAPANESE
私はexcersizeの概念がわかりません。
BACK INTO ENGLISH
I do not understand the concept of excersize.
INTO JAPANESE
私はexcersizeの概念を理解していません。
BACK INTO ENGLISH
I do not understand the concept of excersize.
You've done this before, haven't you.