一、修改用(modify 1 (age 26))，复制用(duplicate 4(name"zhoudahua"))，这两个操作产生的事实产能用于有序事实，有关系名没有相应自定义模板的事实为有序事实。修改通过撤销原事实生成新的事实而成。
二、实例
CLIPS> (facts）
f-0(initial-fact)
f-1(person (name "zhangsan") (age 25) (eye-color blue) (hair-colorblack))
f-4(person (name "zhouhua") (age 65) (eye-color blue) (hair-colorred))
For a total of 3 facts.
CLIPS> (modify 1 (age 26))
CLIPS> (duplicate 4(name "zhoudahua"))
CLIPS> (facts)
f-0(initial-fact)
f-4(person (name "zhouhua") (age 65) (eye-color blue) (hair-colorred))
f-6(person (name "zhangsan") (age 26) (eye-color blue) (hair-colorblack))
f-7(person (name "zhoudahua") (age 65) (eye-color blue) (hair-colorred))
For a total of 4 facts.