1. U 性别，性　 condition of being male or female; gender
2. U 性行为，性吸引，性感　 activities that lead to and include sexual intercourse; mutual physical attraction between people
3. C 男性；女性；雄性；雌性　 either of the two groups that people, animals and plants are divided into according to their function of producing young

　betray one's ～　暴露自己的性别
　discuss ～　讨论性问题
　disguise the true ～　隐瞒自己的真实性别
　have ～ with sb　与某人发生性关系
　improve one's ～ life　改善性生活
　both ～es　男性和女性
　fair ～　女性
　female ～　女性
　gentle ～　女性
　male ～　男性
　opposite ～　异性
　the other ～　异性
　the third ～　（总称）搞同性恋的人
　～ discrimination　性别歧视
　～ manual　性知识手册
　～ organs　性器官
　～ shop　性用品商店
　school for both ～es　男女生学校
　differences of ～　性的区别
　a film with lots of ～　有许多性镜头的电影
　persons of different ～　男女
　members of either ～　男女会员

　What sex is this fish?　这条鱼是雌的还是雄的?
　Everyone is welcome, regardless of age or sex.　欢迎大家，无论男女老少一律欢迎。
　In the space marked "sex", put an "M" for male or an "F" for female.　在标明性别的空白处填上M表示男性，填上F表示女性。
　Best grammar schools are single sex.　大部分文法学校都是男女分开的学校。
　They often had sex together.　他们常发生性关系。
　Do you think sex outside marriage is always wrong?　你认为婚外性关系总是错误的吗?
　The couple went for therapy because they hadn't had sex for years.　这对夫妇去接受治疗，因为他们多年没有过性生活了。
　There's a lot of sex and violence in this film.　这部影片中有不少渲染性行为和暴力的镜头。
　He never associated with the sex.　他从不和女性交往。
　Employing just one woman among fifty men is only token recognition of equal rights for the sexes. 　50个工人中雇用了1个女工只不过象征性地承认了男女平等。
　He often talked about the equality between the sexes.　他常常谈论男女平等的问题。
　There has always been some conflict between two sexes.　两性之间从来就有矛盾。

 ♣ the weaker sex
　女性　woman in general
　He always liked to please the weaker sex, but they generally laughed at him.　他总想取悦女性，可是她们通常取笑他。
　That shop caters exclusively to the weaker sex.　那家商店专供妇女需要的商品。

　sex　也可用作动词，表示“区别…的性别”。例如：
　His job is sexing day-old chicken.　他的工作是鉴别出生一天的小鸡的雌雄。

　［派生词］ sexism n.（尤指对女性的）性别歧视，性别偏见‖sexy adj.性感的，有性的吸引力的
　［词源］　拉丁语sexus<古法语sexe（性别）