When a baby's head is stuck in the birth canal for an extended period of time, it cuts off the blood supply to the woman's surrounding organs.

VOA: special.2010.08.09

And the reason is, and this will come up on the problems and a lot of students end up using this equation, which is why I want to head it off and mention it ahead of time, we can't use an equation because this equation is very specific for light.

原因是，很多同学在解题时,都会用这个方程，所以我要,事先提醒你们一下,我们不能用这个方程，因为它只对光是用。

麻省理工公开课 - 化学原理课程节选

It's really hard to think of all stuff off the top of my head.

脑子里一时想到的都说出来还真难呢。

只要是音乐就好 - SpeakingMax英语口语达人

State Department Acting Spokesman Robert Wood says U.S.officials are in contact with regional allies and other concerned governments to try to "head off" the launch.

VOA: standard.2009.03.12

Are there other indicators or tricks or rules of thumb that just off the top of your head come to you as useful mechanisms for doings this as well?

当然还有没有其他的,一些暗示或者说技巧,或者规则之类有用的办法呢？

哈佛公开课 - 计算机科学课程节选

make sense to people. It was like an alarmwent off in my head.

VOA: standard.other

You can talk about the origins of French nationalism in the middle of the eighteenth century, but it's very closely tied to this dynasty, at least until they lop off the guy's head in 1793.

你也可以畅谈在十八世纪中叶,法国民族主义的起源,但是它和法国王朝制联系很紧密,至少直到一七九三年,那个家伙被砍头前都如此

耶鲁公开课 - 欧洲文明课程节选

I hope that you'll have that in the back of your head when we get to the story of Athens and the invention of democracy, because it was off the wall from the perspective of Greek tradition.

我希望,当我们讲到雅典神话,以及民主制的诞生时,你们还记得这点,因为从希腊人的传统观点来看,这是很不寻常的

耶鲁公开课 - 古希腊历史简介课程节选