TOEFL Listening: TPO-TOEFL听力TPO - S32F12ID5C5EHW2FR$

The professor describes a process for making glass disks. Summarize the process by putting the steps in the correct order. A. Glass-like material is ground up and dyed blue or red. B. Powdered material is heated at very high temperatures. C. Crushed quartz and plant ash are heated at low temperatures. D. Containers are broken to remove glass disks.