YOU SAID:

I think that my grandfathe's duck turns into a cat every sunday

INTO JAPANESE

私は私のgrandfatheのアヒルが猫毎週日曜日になると思います

BACK INTO ENGLISH

I would duck my grandfathe becomes the cat every Sunday

INTO JAPANESE

私は私のgrandfatheアヒル毎週日曜日の猫になるだろう

BACK INTO ENGLISH

I would be in my grandfathe duck every Sunday of the cat

INTO JAPANESE

私は私のgrandfatheアヒルに猫の毎週日曜日になります

BACK INTO ENGLISH

I will be every Sunday of the cat to my grandfathe duck

INTO JAPANESE

私は私のgrandfatheカモに猫の毎週日曜日になります

BACK INTO ENGLISH

I will be every Sunday of the cat to my grandfathe duck