Why should she taunt him this way unless she had good grounds?是什么意思？

Why should she taunt him this way unless she had good grounds?

除非她确实有了证据,不然她怎么会对他这样辱骂 呢 ?

why

adv. （用于问句）为什么，为何，（反问，表示不必）何必，（说明理由）为什么；int. 呵唷，哎呀，嗨；n. 理由，原因，说明，难解的问题；

例句
Most people have very little difficulty in seeing why a Van Gogh is a work of genius.
多数人不难理解为什么凡·高的作品是天才之作。

should

应该，将会，可能，本应；

例句
The older child should be able to prepare a simple meal...
那个年纪稍大的孩子应当会做一顿简单的饭菜。

she

pron. 她，它；

例句
Her lover walked out on her after she had aborted their child.
她的情人在她打掉胎儿后甩了她。

taunt

vt. 嘲笑，奚落，用嘲笑刺激；n. 嘲弄，奚落，讥讽，嘲弄的对象，笑柄；adj. [航]（桅杆）很高的；

例句
He became a taunt to his neighbours.
他成了邻居们嘲讽的对象.

him

pron. (he的宾格)他；

例句
They said goodbye to him as he got aboard the train at Union Station.
当他在联合火车站登上火车之际，他们向他道别。

this

pron. 这，这个，这事，这人，这时，下面所说的事；adj. 这，这个，刚过去的，即将到来的，今…，本…；adv. 这样地，就是这样，这么地；

例句
Victoria Falls has had above average levels of rainfall this year...
维多利亚瀑布今年的降雨量超过了平均水平。

way

n. 道路，方法，方向，某方面；adv. 远远地，大大地；

例句
The way that American history is taught may change in order to accommodate some more of those cultures.
美国历史的授课方式可能会为了照顾到更多的文化而作改变。

unless

conj. 除非，如果不；prep. 除了，…除外；

例句
No-one can set up a waste disposal company unless they can show that they've got enough money and trained staff to do the job properly...
任何人若想成立废品处理公司,必须证明其拥有足够资金和受训员工以保证工作可以顺利开展。

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

good

adj. 好的，优秀的，有益的，漂亮的，健全的；n. 好处，利益，善良，善行，好人；adv. 同well；

例句
This recipe makes a good accompaniment to ice-cream.
这道食谱适合搭配冰激凌。

grounds

n. 庭院，理由，渣滓，泥土( ground的名词复数 )，地面，[航海学]底，（工作、讨论等的）范围；

例句
She is going to divorce him on the grounds of adultery.
她以丈夫搞婚外情为由要求离婚。