you eat the correct foods be able to keep fit and stay healthy .A. Only if will youB. On

问题补充：

you eat the correct foods be able to keep fit and stay healthy .

A. Only if , will you

B. Only if , you will

C. If only , will you

D. Unless , you will

答案：

(答案→)A. Only if , will you

B. Only if , you will

C. If only , will you

D. Unless , you will

解析：考查only的倒装句。Only倒装符合两个条件：Only放在句首，且强调状语的时候，使用部分倒装的形式。本题A选项均符合。句意：只有当你食用正确的食物的时候，你才能保持健康。故A正确。