每天一个生活口语话题，一段地道的举例回答，并附有详细的词汇，发音及用法讲解。讲解材料选自当今最先进最有效的英语原版教材，更加贴近生活。每天坚持听讲解，并根据问题练习，给自己一个地道输入和输出的机会，你也可以张口自信说英语。

主题：What was the best invention of the last 50 years?

I have to say 3D-printing. The process known as additive manufacturing is still in its early stages, but the impact will be enormous. Gone will be assembly lines, long waits for products, and massive storage facilities. We can produce things locally that used to be kept in warehouses. Tools and equipment can be created without needing materials from several suppliers, as can life-changing medical parts such as artificial limbs.

Additive manufacturing: 添加制造
Assembly lines: 装配线
Artificial limbs: 假肢