healthy是形容词，没有复数，例如：
1、Mary gave birth to a healthy baby girl.玛丽生了个健康的女婴。
2、She was delivered of a healthy boy.她生下一个健康的男孩儿。
3、The company made a healthy profit on the deal.公司在这笔生意中获利颇丰。
4、First， some basic facts about healthy eating!首先，说说健康饮食的几点基本事实！
