YOU SAID:

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

INTO JAPANESE

私は私の祖父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 grandfather is the cat every Sunday

INTO JAPANESE

私は私の祖父のアヒルだろう毎週日曜日猫です

BACK INTO ENGLISH

I am every Sunday cat would duck of my grandfather

INTO JAPANESE

私は私の祖父のアヒル毎週日曜日の猫だろう午前

BACK INTO ENGLISH

I am would be my grandfather duck every Sunday of the cat

INTO JAPANESE

私は猫の祖父鴨毎週日曜日になります

BACK INTO ENGLISH

I will be the grandfather duck every Sunday of the cat