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

你，你上课点也没专心，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，让我们回顾下今天节目中词汇，从鼓捣开始，这非正说法，漫不经心地摆弄某物，不出于正当理由。

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——以有趣方花时间摆弄它们。

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人闲聊时候，有些对话我人生中最有意思些了。