The verb 'to be' in English is used as a main verb or an auxiliary verb. As a main verb, it means 'to exist.' As an auxiliary verb, it helps to show tense.
Verb 'Be' (Present) Chart - TEFL Lessons
To Be and To Have Verbs Twinkl Teaching Wiki - Twinkl
How does the word 'AM' change when used in different tenses? - Quora
Verb to be
free worksheets verb to be am is are. English grammar for kids, English grammar, Grammar for kids
Verb To Be: Present, Past, & Future - LANGUAGE ON Schools
To be Interrogative English Grammar A1 Level
English Exercises: Verb to ´be´ : am/is/are
Yes/No Questions With TO BE - English Study Page
Present Simple: How to Use the Verb To Be (Affirmative, Negative, and Interrogative) English Grammar
English is FUNtastic: The Verb «To Be» - rules and examples