英汉词典

1. 一时糊涂；头脑发热
    If you have a brainstorm, you suddenly become unable to think clearly.

    e.g. I can have a brainstorm and be very extravagant.
           我有时会头脑发热，挥霍无度。

2. 突然想到的好主意；灵感
    If you have a brainstorm, you suddenly have a clever idea.

    e.g. 'Look,' she said, getting a brainstorm, 'Why don't you invite them here?'
           “对了，”她灵机一动说道，“你干吗不请他们到这儿来？”