demonstrator

US /ˈdem.ən.streɪ.t̬ɚ/
UK /ˈdem.ən.streɪ.t̬ɚ/
1.

người biểu tình

a person who explains how something works or how to do something:

:
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A demonstrator was showing customers how the food processor worked.
:
demonstratedemonstration