她挖空心思要找出他的动机来.用英语怎么说？

她挖空心思要找出他的动机来.

She rummaged her brain for a reason.

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。

rummaged

v. 翻找，搜寻( rummage的过去式和过去分词 )，已经海关检查；

例句
I rummaged through the drawers and came up with Amanda's folder. 'Here we are.'
我翻遍了抽屉，找出了阿曼达的文件夹。“找到了。”

her

pron. (she的宾格)她，(she的所有格)她的，她，指某个国家，（一艘）船；

例句
There was a terrible sadness in her eyes...
她眼神中流露出深深的悲伤。

brain

n. 脑，智慧，聪明的人，（群体中）最聪明的人；vt. 打破…的脑袋，打…的头部；

例句
As we fall asleep the amplitude of brain waves slowly becomes greater.
进入睡眠状态时，我们的脑电波振幅慢慢变大。

for

prep. 为，为了，倾向于，关于，当作；conj. 因为，由于；

例句
I've come looking for a bit of advice.
我特来讨教。

reason

n. 理由，原因，理性，理智；vt.& vi. 推理，思考，争辩，辩论，向…解释；

例句
As always, Peter had a reason for his action...
一如往常，彼得对自己的行为总有说辞。