Answer:
Taught
Step-by-step explanation:
Most verbs in English are regulars when they're in their past and participle past forms. When they're regulars, they end with "-ed", such as the verbs "stayed," "cried," "cared," "behaved" and "typed". However, there are some verbs that do not follow that same pattern of inflection, those are called "irregular verbs."
The verb "teach" falls into that category of irregular verb because it does not have the "-ed" ending: The past and the past particle of "teach" is "taught".
Ryan taught us about some memorable moments in school history.