1. healthy 有兩個意思，一是指“人本身健康的”，二是指“有益于健康的”。如：
Good food keeps you healthy. 好的飲食使你健康。
Cycling is certainly healthier than driving. 騎車肯定比開車有利于健康。
有時(shí)用于比喻義。如：
That book is not healthy reading for children. 那本書供小孩讀不健康。
2. healthful通常只表示“有益于健康的”。如：
Doing morning exercises is very healthful. 做早操對健康很有益。
Why don't you eat such healthy [healthful] foods? 你為什么不吃那些有益于健康的食物?
此詞在現(xiàn)代英語中用得不多(已屬過時(shí)用法)，一般用healthy代替。
