短语讲解：
1. The light switches on and off rapidly and in different patterns.
switch on打开, 开动, 启动
例句：First you should switch the machine on.
你得先把机器打开。
2. Below is a receiver, which picks up the light variations and translates it back to normal data.
pick up拾起, 捡起; 抬起
例句：I would have picked it up if I had noticed it.
我如果看见的话, 我早就把它拣起来了。
3. Fraunhofer Researcher Dr Jelena Vucic says it is not important what kind of lights are used but the researchers at Fraunhofer have focused on light-emitting diode or LED lights, because they believe it is the "lighting source of the future."
