YOU SAID:
Don't look a gift-horse in the eye.
INTO JAPANESE
ギフト用の馬を目で見ないでください。
BACK INTO ENGLISH
Do not look at the gift horse.
INTO JAPANESE
贈り物の馬を見ないでください。
BACK INTO ENGLISH
Do not look at the gift horse.
That didn't even make that much sense in English.