1. 使(优点)突出;衬托出
    If one thing complements another, it goes well with the other thing and makes its good qualities more noticeable.

complement

    e.g. Nutmeg, parsley and cider all complement the flavour of these beans well.
           肉豆蔻、西芹和苹果酒都能很好地突出这些豆子的味道。

2. 补足;补充;与…相辅相成
    If people or things complement each other, they are different or do something different, which makes them a good combination.

complement什么意思

    e.g. There will be a written examination to complement the practical test...
           会有笔试作为实践考试的补充。
    e.g. We complement one another perfectly.
           我们相互取长补短，堪称完美。

3. 衬托物;补足物
    Something that is a complement to something else complements it.

    e.g. The green wallpaper is the perfect complement to the old pine of the dresser...
           绿色的墙纸完美地衬托出衣橱那年代久远的松木。
    e.g. Political knowledge is a necessary complement to science in approaching solutions to these problems.
           在寻找解决这些问题的方法时，需要有政治知识作为对科学知识的补充。

4. 装备定额;编制名额
    The complement of things or people that something has is the number of things or people that it normally has, which enable it to function properly.

    e.g. Each ship had a complement of around a dozen officers and 250 men...
           每艘船的编制人数约为军官12位，船员250名。
    e.g. Not one house on the Close still had its full complement of windows.
           克洛斯岛上没有一所房子的窗户仍旧是齐全的。

5. 补语
    In grammar, the complement of a link verb is an adjective group or noun group which comes after the verb and describes or identifies the subject. For example, in the sentence 'They felt very tired', 'very tired' is the complement. In 'They were students', 'students' is the complement.