Sentence:  Exposing one's self to a severely communicable disease in order to alleviate that individual's suffering, e.g., working in a tubercular ward in the early part of this century, or working in an AIDS hospice today, could be seen as <WSD>supererogations</WSD> of type one. Providing cosmetic surgery, not as the repair of a disfigurement caused by accident or injury, but simply to enhance one's features, or providing Human Growth Hormone so one may not be considered short, would be examples of <WSD>supererogations</WSD> of type two. 
Meaning of the word marked with <WSD> tags:  An action that is neither morally forbidden nor required, but has moral value.