element-expression

    Specifies one or more elements whose generations are to be
    inserted into the class. An element expression can be an element
    name, a group name, a wildcard expression, or a list of these
    separated by commas. By default, the most recent generation on the
    main line of descent is inserted.

 class-expression

    Specifies an established class into which the element generation
    is being placed. The class must not have the read-only attribute.
    A class expression can be a class name, a wildcard expression, or
    a list of these separated by commas.

 remark

    Specifies a character string to be logged in the history file
    with this command, usually used to explain why the command was
    entered. The remark is enclosed in quotation marks. If no remark
    was entered, a null remark ("") is logged.