Put that knife down before you hurt somebody!

把刀子放下，别伤着人！

《牛津词典》

I strolled up and down thoughtfully before calling a taxi.

叫出租车前,我若有所思地来回踱步。

《柯林斯英汉双解大词典》

He looked down at the sea of smiling faces before him.

他看着眼前这笑脸的海洋。

《牛津词典》

Before the flight went down, sensors gave conflicting information on air speed to the plane's computers, possibly because of ice.

VOA: special.2009.06.13

Because it says, your program will still give you a value, but it may not be what you intended, and you can't always tell, and that may propagate it's way down through a whole bunch of other computations before it causes some catastrophic failure.

因为这意味着，你的程序依然会返回一个值，但是这个值可能不是你想要的，你可能还分辨不出来，而且这种情况会传播,结果会沿着正果计算过程传播下去,直到产生一个灾难性的错误。

麻省理工公开课 - 计算机科学及编程导论课程节选

Everyone was scrambling to get a house before they shut down the housing market.

人人争先恐后,就是为了赶在房地产市场关闭前买到房

耶鲁公开课 - 金融市场课程节选

He'd played 12 seasons as an offensive lineman in Baltimore, 11 of them Pro Bowl ones, won a Super Bowl too, and a few minutes before down the street, he'd been handed the most indelible honor in the game: induction to the Pro Football Hall of Fame.

WSJ: Super Bowl: The Night (Half) the Lights Went Out

Warrington's Matt King fumbled one Lee Briers kick into the corner before touching down a second to get his side on the scoresheet before half-time.

BBC: Warrington 16-8 Wigan

It rocketed up to a mere 55, 000 feet before shutting down and gliding back to terra firma, an important first step before a full-altitude flight later this year and planned commercial flights in 2015.

ENGADGET: Editor's Letter: Welcome to May