You, you're not concentrating at all. You just muck about.

你，你上课一点也没专心，一直在闲游。

OK, let's recap the vocabulary from this programme, starting with mucking about, an informal way to say playing with something carelessly, not for a serious reason.

好的，让我们回顾一下今天节目中的词汇，从鼓捣开始，这是一种非正式说法，指的是漫不经心地摆弄某物，不是出于正当理由。

After the year 2000, 3D printers suddenly got much cheaper and tech companies started mucking about with them – spending time playing with them in a fun way.

2000年之后，3D打印机突然便宜了很多，科技公司开始鼓捣它们——以一种有趣的方式花时间摆弄它们。

And yet, if you muck about with people who are doing artificial intelligence, some of the discussions are the most fascinating discussions I've ever had in my life.

不过如果跟人工智能领域的人闲聊的时候，有些对话是我人生中最有意思的一些了。