betty has just told us all that what has happenedto her is n

what 关系代词
has happened to 短语动词作谓语
her 宾语
(what has happened to her 主语从句)
is nothing serious 系表结构 serious是nothing定语,后置定语.
at all 状语
that what has happened to her is nothing serious at all.)宾语从句.