YOU SAID:
i saw your mother the day before last in the store buying condoms for me
INTO JAPANESE
一昨日、店であなたのお母さんが私のためにコンドームを買っているのを見ました
BACK INTO ENGLISH
The day before yesterday I saw your mother buying condoms for me in the store
INTO JAPANESE
一昨日、あなたのお母さんが店で私のためにコンドームを買っているのを見ました
BACK INTO ENGLISH
The day before yesterday I saw your mother buying condoms for me in the store
You've done this before, haven't you.