老师演示了如何使用这个设备。

The teacher ___demonstrated how to use the equipment.

他有一份在百货商店演示厨房设备的工作。

He's got a job ___demonstrating kitchen equipment in a department store.

我可以向人们演示如何制作堆肥坑，并利用厨房垃圾为他们的花园生成堆肥。

I could ___demonstrate to people how to create compost pits and use kitchen waste to generate compost for their gardens.