1. 男性;女性;雌性;雄性
    The two sexes are the two groups, male and female, into which people and animals are divided according to the function they have in producing young.

sex

    e.g. ...an entertainment star who appeals to all ages and both sexes.
           男女老幼都喜欢的娱乐明星
    e.g. ...differences between the sexes.
           两性之间的差异

2. 性别;性别特征
    The sex of a person or animal is their characteristic of being either male or female.

    e.g. She continually failed to gain promotion because of her sex...
           她因为是女性而迟迟得不到晋升。
    e.g. The new technique has been used to identify the sex of foetuses.
           这一新技术已经被用来鉴别胎儿的性别。

3. 性行为;性交;性活动
    Sex is the physical activity by which people can produce young.

    e.g. He was very open in his attitudes about sex...
           他对待性的态度非常开放。
    e.g. The entire film revolves around drugs, sex and violence...
           整个影片围绕着毒品、性和暴力展开。

4. 辨别…的性别;辨识…的雌雄
    If an animal is sexed, someone finds out whether it is male or female.

    e.g. The birds must be weighed, sexed and tagged.
           必须对这些鸟称重，辨识雌雄并挂上标牌。

5. 发生性关系;做爱
    If two people have sex, they perform the act of sex.

    e.g. I had no intention of having sex with him on a first date.
           我并没想第一次约会就和他上床。

相关词组：sex up