Pliny and the Greek geographer Strabo both noted that slaves making cloth with the material developed lung problems.

VOA: special.2009.11.17

They're actively engaged in the material, actually seeing the phenomena, by making measurements of real world experiments.

学生们能自主地参与到物质中，看见真切的现象，通过对真实世界实验,做出测量。

麻省理工公开课 - 媒体、教育、市场课程节选

It is not about making the material relevant and easy to apply in given opportunities to do that. It is not about creating interaction in community.

不是整理相关材料,以便于时机适宜时容易,利用，不是,在社群内进行互动。

麻省理工公开课 - 媒体、教育、市场课程节选

You can also perform a test. Take some of the material and add enough water to it to make it seem like you are making bread.

VOA: special.2009.09.14

Then,she started making statues out of cement material and glass.

VOA: special.2010.04.14