主题：每日口语keep one's head

例句：
Mr. White can keep his head in any emergency; he is never likely to panic.
怀特先生在任何紧急情况下都能保持镇静，从不会惊慌。

2 do sth. off the top of one's head

毫无准备地干什么事情，临时应付

例句：
I'll just have to give the speech off the top of my head. There's no time to write it down.

没有时间写讲稿，我只好即席发言。