YOU SAID:

i do not know what this is for

INTO JAPANESE

私はこれが何のためかわからない

BACK INTO ENGLISH

I don't know what this is for

INTO JAPANESE

理解できんのだ

BACK INTO ENGLISH

I don't know what this is.

INTO JAPANESE

理解できんのだ

BACK INTO ENGLISH

I don't know what this is.