brain

这会儿我的脑子不好使。

My ___brain isn't working well now.

锻炼大脑的一个好方法是每天做一些数学练习。

A good way to train the ___brain is to do some math exercises every day.

如果你对某事感兴趣，你的大脑就会更活跃。

If you are interested in something, your ___brain is more active.