Hair's natural shine is supplied by its own conditioner, sebum, an oil composed of waxes and fats and also containing a natural antiseptic that helps fight infection. Too much sebum results in greasy hair and conversely, too little sebum makes dry hair.
头发的自然光泽来自它自身的护发素：油脂，它含有蜡和脂肪，还含有抗感染的自然抗菌剂。油脂含量过多会导致油性发质，相反，油脂含量过少则会导致干性发质。
conversely, work in applied science and technology frequently acts as a direct stimulus to the development of pure science.
相反，应用科学技术的成果在纯科学的发展中经常起到直接的促进作用。
conversely, intelligent beings which are just beginning to develop on remote worlds may be ready to pick up our signals in thousands of years.
反过来说，其他星球上的刚刚开始进化的智力生命，他们要过几千年之后，也许才可能收到我们的信号。
