1. （使）交替；（使）轮流
    When you alternate two things, you keep using one then the other. When one thing alternates with another, the first regularly occurs after the other.

    e.g. Her aggressive moods alternated with gentle or more co-operative states...
           她情绪多变，时而咄咄逼人，时而又显得温柔平和或乐于合作。
    e.g. The three acts will alternate as headliners throughout the tour...
           这3个节目将在整个巡回演出中轮流打头牌。

2. 交替的；轮流的
    Alternate actions, events, or processes regularly occur after each other.

    e.g. They were streaked with alternate bands of colour.
           它们都带有各种色彩相间的条纹。

3. 每隔一（天等）的
    If something happens on alternate days, it happens on one day, then happens on every second day after that. In the same way, something can happen in alternate weeks, years, or other periods of time.

alternate是什么意思

    e.g. Lesley had agreed to Jim going skiing in alternate years.
           莱斯莉已同意吉姆每隔一年去滑一次雪。

4. 供选择的；备用的；其他的
    You use alternate to describe a plan, idea, or system which is different from the one already in operation and can be used instead of it.

alternate

    e.g. His group was forced to turn back and take an alternate route.
           他的小组被迫返回并选择了另一条路线。
    e.g. ...alternate forms of medical treatment.
           其他可供选择的医疗方案

5. 代替者；候补者
    An alternate is a person or thing that replaces another, and can act or be used instead of them.

    e.g. In most jurisdictions, twelve jurors and two alternates are chosen...
           大多数辖区都会选出12名陪审员和2名候补陪审员。
    e.g. The six food groups include grain products, vegetables, fruits, milk and milk products, meats and meat alternates, and a miscellaneous group.
           这6类食物包括谷类产品、蔬菜、水果、牛奶和奶制品、肉类和肉类替代品以及杂类食品。

6. （尤其在美国英语中，当alternative作义项3、4和5解时，代替alternative使用）
    Alternate is sometimes used, especially in American English, instead of alternative in meanings 3, 4, and 5.

    e.g. ...an alternate lifestyle.
           另一种生活方式