Apply a default value, for example a hyphen (-), to make the attributes display that they are currently holding no value.

应用一个默认的值，例如一个连字符(-)，以显示当前没有任何值的属性。

youdao

The hyphen (-) used to separate words in the W3C CSS Version 2.0 specification isn't used as part of the code convention in the Flex implementation.

在W3C CSS版本2.0中被用来分离单词的连字符(-)并未用作Flex实现内的代码约定的一部分。

youdao

The article al (also written as el) may be attached to surnames directly, separated from surnames with a hyphen or a space, or omitted altogether.

词条al(阿拉)可以写为el(艾拉)，它可以直接通过使用连字号或空格与人的姓氏写在一起，或省掉不写。

youdao

The label in question was one he disliked so much that he preferred to put it between quotation marks (as if handling it with a pair of tweezers) and to insert a hyphen (as if to deny it the dignity of being a real word).

NEWYORKER: Politics and Prose

The addition of a hyphen to her surname for the purposes of her title was required under peerage rules, she confirmed.

BBC: Digital boss Martha Lane Fox to get peerage