Target object can be required or optional.
目标对象可能是“必需的”也可能是“可选的”。
University Classes, Required or Optional?
大学课程是强制还是选择？
The required or optional nature of a piece of data.
一段数据天生具有的必需或是可选的属性。
Any required or optional service data inputs and outputs.
任何被要求或者可选的服务数据输入和输出。
Most job types have one or more required or optional parameters.
大多数作业类型都拥有一个或多个必需或可选参数。
Right-click menus are used to easily guide the user in designating elements as required or optional.
用户可以使用右击菜单将元素指定为必需的或可选的。
Preferably, use instructional text to indicate required or optional fields, but asterisks also work for required fields.
最好是用提示性文字去标注必填还是可选填，但用星号也可以标注必填。
You invoke the function simply by calling its name and passing on to it any further required or optional input parameters.
调用函数的方法是调用它的名称并传递必需的或可选的输入参数。
However, this WSDL file, or the contract, does not declare which element (s) may be a required or optional variable for the invocation.
然而，WSDL文件，或者说协议并没有指明哪一个元素是调用服务必须的或可选的变量。
These rules describe, for example, which elements are valid, the order of elements within a document, the data types of attributes, whether an element is required or optional, and so on.
这些规则定义哪些元素是有效的、文档中元素的次序、属性的数据类型、一个元素是必需的还是可选的等等。
You can even make fields optional or required.
甚至还能将字段设置为可选或必需的。
Optional elements can be omitted or required.
可以忽略或要求可选的元素。
Additionally, determine how making a specific optional field into a required field or adding a new value to a selection list can be accomplished.
此外，还要确定如何把某个可选字段变为必需字段或者向选择列表增加的新值。
Note: parameters shown in Angle brackets are optional; parameters or options shown in normal brackets () are required and must be provided.
注意：尖括号中的参数为可选参数；方括号()中的参数或选项为必需参数，必须提供。
Control-flag: This defines the behavior of stacking modules by specifying whether any particular module is requisite, required, optional, or sufficient.
Control -flag：这指定任何特定模块是必不可少的、必需的、可选的还是足够的，从而定义模块的行为。
You can designate parameters as optional or required in the XSL: param element, except when that element is a child of XSL: function, in which case they are always required.
可以在xsl：param元素中指定参数是可选或必须的，除非该元素是xsl：function的子元素，这种情况下参数是不可少的。
For example, the table below, while not comprehensive, describes a few pipeline-related plugins in terms of their importance to pipeline functionality (required, recommended, or optional).
例如，下面的表格并不全面，描述了一些管道相关的插件在管道功能(必需，推荐或可选)方面的重要性。
Additionally, a usage of the requirement can also be set as required, optional, or prohibited through the use attribute (the default value is required).
此外，需求的使用还可以通过use属性设置为required,optional或prohibited(默认值为required)。
Optional resources are things like document templates or other resources that are useful to an application but not required for it to launch.
可选的资源文件是那些如文档模板等对程序有用但是不是启动程序必须的资源文件。
Optional resources are things like document templates or other resources that are useful to an application but not required for it to launch.
可选的资源文件是那些如文档模板等对程序有用但是不是启动程序必须的资源文件。
应用推荐