必选

• All five pieces of information are required
  （这五项信息均为必选。 ）
• Value from which you want to extract the second
  必选。要从中提取秒的
• Value from which you want to extract the month
  必选。要从中提取月的
• Required arguments are those that must always be specified
  必选参数是必须始终指定的参数。
• Key from which the value is to be retrieved
  从中检索值的项。必选。
• Value from which you want to extract the year
  必选。所要提取年份的
• Expression that specifies the name of the file to be copied
  必选。指定要复制的文件名称的
• The name of the element to be created is specified by a required
  要创建的元素的名称由必选的
• Options required for publishing test results
  发布测试结果的必选选项
• Validation checks that any required attributes are included
  验证检查是否包括所有必选属性。