YOU SAID:

Potatoes are good when fried

INTO JAPANESE

ジャガイモは揚げば良いです

BACK INTO ENGLISH

Potatoes should be fried

INTO JAPANESE

ジャガイモは揚げなければならない

BACK INTO ENGLISH

Potatoes must be fried

INTO JAPANESE

ジャガイモは揚げなければならない

BACK INTO ENGLISH

Potatoes must be fried