She wasn't very [focus] or interested [in] what I was saying

如果这是语法考试,这个句子（如你所说）无疑是有问题的,
但作为口语,这个语法上有点马虎的句子是可以接受的,
句子其实可以理解为
(Either) she wasn't very focussed (on what I was saying),or (she wasn't) interested in what I was saying.
其中括号内的单词被省略了,而且,省略的另一个原因是避免重复.
对英语为第一语言者来说,省略这些单词不影响句子的语境和可理解度,因此一般人对这个句子不会太拘泥.
我是加拿大人,前英语老师.