head

我无法入睡，因为这个问题一直在我脑海里盘旋。

I couldn't sleep because the problem was going round in my ___head.

然后那个想法突然出现在我脑海中。

Then suddenly the idea came into my ___head.

我的头感觉很烫。

My ___head feels very hot.

请当心碰头！

Mind your ___head, please!