YOU SAID:
You don't know me, but my names si.
INTO JAPANESE
私は、私の名前の si が知らない。
BACK INTO ENGLISH
I don't know the name of my si.
INTO JAPANESE
私は私の妹の名前を知らない。
BACK INTO ENGLISH
I do not know my sister's name.
INTO JAPANESE
私の妹の名前がわからない。
BACK INTO ENGLISH
My sister's name is not known.
INTO JAPANESE
私の妹の名前は知られていません。
BACK INTO ENGLISH
My sister's name is not known.
Well done, yes, well done!