have sth. on the brain

例句：

1. 1. I've been thinking about what to cook for dinner all afternoon.
   我整个下午都在想着晚餐要做什么。
2. 2. She was so focused on her work that she didn't realize she had fallen asleep.
   她太专注于工作了，以至于没有意识到她已经睡着了。
3. 3. He spent hours thinking about how he could improve his business strategy.
   他花了很多小时思考如何改进他的商业策略。