An app can be as simple as a program that turns a mobile phone into a flashlight to light your way at night.

VOA: special.2011.03.22

And this is a very fast speed, of course, it's about 700 million miles per hour. So, one way to put that in perspective is to think about how long it takes for a light beam to get from earth to the moon. Does anyone have any guesses? Eight seconds, that sounds good.

当然这是一个非常快的速度，它大约是每小时7亿英里,为了更形象化，我们,看看光从地球到月球,需要多少时间，你们猜猜是多少？,8秒，猜的不错。

麻省理工公开课 - 化学原理课程节选

"Some of these inventors have been designers of the human genome sequencer, incredible technologies around focusing sound in the same way have been able to focus light with lasers, health technologies like the stair-climbing wheelchair and a portable dialysis machine,".

VOA: standard.2009.12.18